Projects

The Center for Detectors designs, develops, and implements detectors to enable scientific discoveries.

NRT: Convergent Graduate Research Training for CMOS+X Semiconductor Technologies
PI: Jing Zhang
September 2024 - August 2029

Our NRT program at RIT aims to develop an innovative convergent graduate research training model for next-generation complementary metal-oxide-semiconductor (CMOS) +X (X = AI, biomedical, chemical, optoelectronic, photonic, nanoelectronic, quantum, and packaging) talents, in order to address this urgent national talent shortage. We plan to fulfill our convergent training and research goals in semiconductors by expanding on our existing Microsystem Engineering Ph.D. program with inclusions of trainees and resources from Ph.D. programs in Physics, ECE, Chemical Engineering, and Biomedical Engineering. Our NRT trainees will be equipped with both technical and professional skills needed for next-generation semiconductor technologies.

X-Ray and UV Optics for Light-Source and Astronomical Applications
PI: Zoran Ninkov
July 2024 - June 2026

Optimax develops high-precision optics and coatings for scientific and industrial applications. They are interested in expanding into the DUV/X-ray optics market, and they are seeking technical analysis and insight from RIT to support this development. It is known that the majority of applications for x-ray optics are to be found in medical, scientific (synchrotron beamlines and plasma diagnostics), and astrophysical instrumentation; Optimax is interested in the astrophysical and extreme-materials applications (not medical). At the optical systems level these applications share much in common. RIT will perform a survey and measurements of instrumentation systems that utilize x-ray optics, including x-ray source optics (beamlines), x-ray collimation/imaging, and DMDs with emphasis on scientific and astrophysical instrumentation.

Beginnings: Empowering Minds through Experiential Learning, Research, and Career Growth Opportunities in Emerging Microelectronics (EMERGE-MICRO)
PI: Parsian Katal Mohseni
July 2024 - June 2026

Rochester Institute of Technology proposes to develop an experiential learning initiative that is intended to serve as a pilot model toward sustaining a vibrant future for the US semiconductor industry. The proposed program will establish a comprehensive approach that leverages collaborations between academia and industry. This effort will cultivate a skilled and adaptable workforce for the emerging technology fields of semiconductors and microelectronics. Moreover, it will support the continued growth of the microelectronics industry and safeguard the nation's technological leadership on the world stage.

In(Ga)As/GaAs Quantum Dot Development for SWIR Sensing Applications by MOCVD
PI: Parsian Katal Mohseni
May 2024 - February 2025

RIT will design and conduct crystal growth of In(Ga)As/GaAs quantum dots on GaAs substrates via metalorganic chemical vapor deposition, targeting room-temperature photoluminescence emission at telecom wavelengths. Materials characterization will be performed through photoluminescence spectroscopy, X-ray diffraction, atomic force microscopy, and transmission electron microscopy.

Efficient Non-Linear Optical Hybrid Quantum Photonic Integrated Circuits Fabricated with CMOS Foundry Compatibility
PI: Stephan Preble
February 2024 - February 2025

The overall goal of this AF SBIR effort is to efficiently integrate a second order non-linearity into the well-established Silicon on Insulator (SOI) foundry-scale fabrication process. The initial demonstration will target fabrication of hybrid quantum photonic integrated circuits (Q-PICs) for interfacing atomic memories with transitions in the visible wavelength range across existing telecom fiber optic links. AdvR and RIT will work together to demonstrate robust measurable coupling between the SiN waveguides and a bulk periodically poled NLO substrate. The key innovation is the efficient integration of foundry fabricated 300 mm Silicon Nitride (SiN) waveguides with small period, periodically poled potassium titanyl phosphate (PPKTP), for generation of visible light photons and efficient electro-optic modulation. Utilizing bulk KTP instead of thin film lithium niobate will ease the fabrication constraints since KTP has a lower optic index (~1.8) and thus its thickness does need to

Applications of Modeling to Extend Nanolithography
PI: Stephan Preble
December 2023 - June 2024

The application of nanolithography to device technology continues beyond 5nm nodes as EUVL, High NA EUVL, optical extensions, multiple patterning, and other alternatives are considered. The demands on lithography systems and processes become increasingly difficult. Collaboration between groups associated with the research, development, application, and modeling of systems and processes is critically important for the success of future device generations. Rochester Institute of Technology (RIT) and Siemens Industry Software Inc. (SISW) share a common interest to explore the challenges involved. To carry this out, continuation of an established internship program is proposed to allow the placement of a Ph.D. student from RIT's Microsystems Engineering program in the College of Engineering at IMEC in Belgium, supported by SISW to carry out these activities of common interest.

Conference: Diffuse Cosmic Backgrounds and the Low Surface Brightness Universe
PI: Micheal Zemcov
March 2024 - April 2024

The background radiation at optical and near-infrared wavelengths is thought to be sources largely by stars in galaxies, but tensions in recent measurements indicate that our census of galaxy populations might be incomplete. A significant fraction of light might be sourced by low surface brightness stellar populations and new high-redshift populations whose roots trace back surprisingly early in the history of galaxy assembly. In this conference, we will bring together experts in the history of galaxy formation, low surface brightness populations, the cosmic background light, and astrophysical theory to discuss how to reconcile the observations and their implications for cosmic structure formation.

Rochester Education & Workforce Development 2024
PI: Stephan Preble
April 2024 - March 2025

This is year 3 of the AIM Photonics Rochester Education & Workforce Development Project.

Advancing Radiation-Hardened CMOS Deterctors for NASA Missions
PI: Donald Figer
January 2024 - January 2027

We propose a comprehensive program to advance radiation-hardened single-photon counting and photon number resolving optical imaging detectors for use in future NASA missions. These detectors use very low-capacitance sense nodes that produce a large voltage response to a single proton. Several companies have commercialized early versions in multi-megapixel format. They operate at near-room temperature and have negligible dark current. Previous results obtained by the proposing team suggest that the degradation in dark current after irradiation up to 50 krad(Si) is at least two orders of magnitude less than for commonly-used CCDs, and better than for previously-available CMOS imagers. The proposed program aims to minimize the transient and long-term effects of radiation in NASA missions that have a wide range of orbital trajectories, including LEO, L2, and near Jupiter's moons where exposure is in the Mrad(SI) level. The program will use existing detectors from several vendors.

Silicon Photonics Integration
PI: Stephan Preble
July 2023 - July 2024

RIT will be supporting Phase Sensitive Innovation in SBIR project NAVY N23B-T034: Silicon Photonics Integration. The focus will be on silicon photonic integrated circuits under extreme conditions.

RIT Semiconductor Fabrication Laboratory
Co-PI: Stephan Preble
March 2023 - March 2024

RIT's semiconductor fabrication laboratories were built in the mid-1980s to provide a state-of-the-art platform for the first ABET-accredited Bachelor of Science in Microelectronics Engineering. Today, the laboratories serve as a backdrop for educating students enrolled in RIT's BS, MS, and PhD programs. The current $2M project will be used to replace aging tools and equipment so that the facility can continue to serve its dual education and research mission. Approximatelyhalf of the current project will be used to replace or upgrade the cleanroom infrastructure and utilities. Examples include air handling and filtration systems, process vacuum, gas handling and monitoring, waste neutralization, and wet processing benches. The remainder of the funding will be used to replace and upgrade processing and metrology tools, including thermal processing furnaces, photoresist coating and developer tracks, and various inspection tools.

RIT/L3Harris Quantum Information Science and Technology Collaboration
PI: Gregory Howland
March 2023 - March 2024

The aim of this work is to develop silicon quantum photonic integrated circuits for high-dimensional quantum information processing.

Advancing Quantum Metrology and Sensing Education: Concepts, Curricula, and Research on Student Learning
Co-PI: Gregory Howland
January 2023 - December 2023

The National Quantum Initiative Act established quantum technology as a national priority because quantum systems will lead to significant improvements in computing, communication, and sensing. However, quantum sensing has received little attention in the media, curriculum development, and education research despite diverse application areas and near-term impacts. This proposal would support three goals: (1) Defining the major concepts and canonical systems of quantum metrology, sensing, and imaging through interviews with experts. (2) Developing flexible and adaptable curricular materials (e.g., lesson plans, active learning tutorials, clicker questions, homework problems). (3) Conducting foundational research on student learning of quantum sensing and metrology. The project will improve the quality of QIS instruction across a range of institutions and levels to better support learners from diverse disciplinary backgrounds and foster inclusive teaching through active learning.

Rochester Education & Workforce Development 2023
PI: Stephan Preble
January 2023 - December 2023

AIM Photonics Academy (AIM Academy) is responsible for building an agile workforce that can opportunistically reskill and upskill to steadily grow the US photonic integrated circuits (PIC) industry. This is year 2 of the AIM Photonics Rochester Education & Workforce Development Project.

Development of High Dynamic Range (HDR) Capabilities of CID Sensors
PI: Zoran Ninkov
January 2023 - August 2024

Charge Injection Device (CID) detector arrays are designed and fabricated with two capabilities not found in most competing technologies, namely random addressability and non-destructive readout (NDRO). This permits many novel readout modalities to be implemented that have not been explored. For example, the ability to segment an image after a rapid initial “guide” exposure into brightness level that then permits bright regions to be exposed, readout, reset and continue to be expose multiple times while fainter regions are integrated for longer. This and other readout approaches depend on the stability of the addressing, reset and readout which will be studied.

Characterizing Single-photon Sensing CMOS Image Sensors for NASA Missions
PI: Donald Figer
September 2023 - August 2025

The proposed project seeks to advance the technology readiness level (TRL) of commercial off-the-shelf (COTS) large-format single-photon sensing and photon-number resolving CMOS (SPSCMOS) optical image sensors for use in future NASA flagship missions, such as for the focal plane of the large optical mission recommended by the Pathways to Discovery in Astronomy and Astrophysics for the 2020s. The proposed program includes detector characterization in the laboratory, at a telescope, and after high energy particle irradiation. The characterizations include read noise, dark current, quantum efficiency, persistence, and linearity. A telescope observation program will demonstrate the technology, preferably on a large telescope, such as the California Institute of Technology Hale telescope at the Palomar observatory.

Collaborative Research: Its TIME! Mapping cosmic star formation history with CO and CII
PI: Michael Zemcov
September 2023 - August 2026

The Tomographic Ionized carbon Mapping Experiment (TIME) is a mm-wave grating spectrometer designed to perform line intensity mapping measurements of CII and CO to trace the formation of structure in the early universe. This proposal funds a graduate student to develop control software for the instrument, data reduction and analysis, and scientific interpretation of the observations over a 3-year program.

Development of High Dynamic Range (HDR) Capabilities of CID Sensors
PI: Zoran Ninkov
January - June 2023

Charge Injection Device (CID) detector arrays are designed and fabricated with two capabilities not found in most competing technologies, namely random addressability and non-destructive readout (NDRO). This permits many novel readout modalities to be implemented that have not been explored. For example, the ability to segment an image after a rapid initial "guide" exposure into brightness level that then permits bright regions to be exposed, readout, reset and continue to be expose multiple times while fainter regions are integrated for longer. This and other readout approaches depend on the stability of the addressing, reset and readout which will be studied.

Rapid Assistance (for) Coronavirus Economic Response (RACER)
PI: Stefan Preble
March 2022 - February 2024

Our proposed effort will complete basic science, engineering, and manufacturing challenges that will enable development of the first point-of-care (POC) diagnostics system centered on integrated photonics. The overall system will consist of inexpensive, disposable photonic test cards able to detect the human response to multiple viral pathogens, and a portable, low-cost assay reader. Our proposed system will leverage the capabilities of AIM Photonics (photonic sensor manufacturing).

Quantum Dot Inspired Overcoating of uLED Mesas
PI: Jing Zhang
July 2022 - June 2023

Copper contamination is often associated with poor performance in III-P LEDs. For this reason, copper contacts and copper electrodeposition methods are frequently avoided in III-P LED manufacturing. However, there is sparse hard evidence that copper ions degrade LED performance. This project seeks to directly test the hypothesis, that copper ion contamination reduces LED efficiency.

Composing the History of Near-IR and Optical Light Production with the Cosmic Infrared Background Experiment-2 (CIBER-2)
PI: Michael Zemcov
September 2022 - August 2026

The Cosmic Infrared Background ExpeRiment-2 (CIBER-2) is a sounding-rocket borne instrume designed to measure anisotropy in the Extragalactic Background Light (EBL) in 6 broad bands covering the optical and near-infrared (near-IR). CIBER-2 builds on the measurement techniques developed and successfully demonstrated by CIBER-1, and provide a testbed for so of the technologies and techniques that will be employed by the upcoming SPHEREx mission. U high-sensitivity, wide-angle, multi-color anisotropy measurements, CIBER-2 will elucidate the his of intra-halo light (IHL) production and carry out a deep search for extragalactic background fluctuations associated with the Epoch of Reionization. This proposal requests support for 2 fligh CIBER-2 and the analysis and interpretation necessary to extract scientific results from the data.

Developing the largest IR detectors for future NASA focal planes
PI: Don Figer
September 2022 - August 2025

The primary goal of the HELLSTAR project is to produce the highest pixel count IR detector ever made for astronomy. We aim to design, fabricate, and characterize a new large format detector using existing ROICs created by Sensor Creations Inc. and the new MCT/Si detector substrate developed by our team and Raytheon Vision Services. Subsequent phases of the project will focus on the development of new readout hardware and software, as well as the characterization and optimization of the HELLSTAR device. The final phase will consist of deployment of the device to a telescope to demonstrate its capabilities, as well as possible deployment in Antarctica via the Cryoscope project. The HELLSTAR detectors will pave the way for extremely large IR focal planes in the next generation of NASA space and ground missions.

Polarimetric Observer Light Analyzing Research (POLAR) Mission
PI: Zoran Ninkov
January 2022 - June 2023

This project plans to explore the use of Polarization Sensitive Focal Plane Arrys for use in small satellite missions. The project will investigate the development of such harware, the calibration of such devices and the incorporation of software to provide near real time information.

Development of DMD Devices
PI: Zoran Ninkov
March 2022 - August 2024

The Sensor Systems Subdivision at Aero Corporation will engage with the research group of Professor Zoran Ninkov of the Center for Imaging Science (CIS) at the Rochester Institute of Technology (RIT) in a collaborative research program to develop a key MEMS component that is optimized for use in the infrared.

Hybrid and Heterogeneous Integration of PICs for RF Photonic Imaging Systems
PI: Stefan Preble
September 2022 - February 2024

The goal of this collaborative effort is to develop high-density heterogeneous and hybrid photonic integrated circuit (PIC) packaging techniques to support the demonstration of an analog RF photonic imaging system-in-a-package.

Studies of the Diffuse Optical Background with New Horizons
PI: Michael Zemcov
September 2018 - September 2022

The goal of this project is to measure the cosmic optical background (COB), which is the sum of all emission from sources beyond the Milky Way at optical wavelengths, using images taken by the Long Range Reconnaissance Imager (LORRI) on New Horizons. This allows for a comparison between this measurement and all expected sources of emission such as galaxies and potential identification of the source of any excess component of diffuse emission.

Over the past year, we have estimated LORRI's dark current stability and calibrated our selected LORRI data in preparation for measuring the COB. We have used a point spread function (PSF) reconstruction algorithm to combine cut-outs of multiple stars in each image and deconvolved these stacked PSFs to return an estimate of the optical PSF. We have also been working on estimating astrophysical foregrounds so that they can be effectively removed from the LORRI images for a more accurate measurement of the COB. These include the integrated star light (ISL), which results from faint stars that cannot be masked out, and the diffuse galactic light (DGL), which is light that is reflected from dust in the Milky Way.

Future plans include improved estimates of the ISL and DGL resulting in a definitive measurement of the COB, estimates of LORRI's pointing stability, and a similar measurement of the COB using the LEISA instrument on New Horizons.

A Single Photon Sensing and Photon Number Resolving Detector for NASA Missions
PI: Don Figer
November 2019 - May 2022

Single photon counting large-format detectors will be a key technology for future NASA Astrophysics missions such as the LUVIOR and HabEx mission concepts. The goal of this project is to characterize and demonstrate single photon-sensing and photon-number resolving CMOS image sensors, developed by Dr. Eric Fossum (Dartmouth College) and his team of graduate students. Following the sensor characterization, we will irradiate one device to simulate damage from high-energy radiation in space while we demonstrate astronomical observations with another device at a telescope. In collaboration with Dartmouth, we will redesign the detector to achieve the science requirements of future NASA missions.

This project involves the work of numerous students, including one Dartmouth College graduate student, four RIT graduate students and seven RIT undergraduate students. The team fabricated the system hardware and electronics necessary to interface and control the QIS with our existing automated test suite. Now, the team is working to complete the Field Programmable Gate Array (FPGA) hardware program, which is responsible for generating system clocks and managing data transfer from the image sensor to a computer.

MISE (The Mid-IR Sky Explorer)
PI: Michael Zemcov
June 2020 - June 2021

Imaging polarimeters utilizing the division-of-focal technique present unique challenges during the data reduction process. Because an image is formed directly on the polarizing optic, each pixel "sees" a different part of the scene; this problem is analogous to the challenges in color restoration that arise with the use of Bayer filters.

Although polarization is an inherent property of light, the vast majority of light sensors (including bolometers, semiconductor devices, and photographic emulsions) are only able to measure the intensity of incident radiation. A polarimeter measures the polarization of the electromagnetic field by converting differences in polarization into differences in intensity. The microgrid polarizer array (MGPA) divides the focal plane into an array of superpixels. Each sub-pixel samples the electric field along a different direction, polarizing the light that passes through it and modulating the intensity according to the polarization of the light and the orientation of the polarizer. We are actively looking at techniques for hybridizing microgrid polarizer arrays to commercial CID, CCD, and CMOS arrays.

Phase II: New Infrared Detectors for Astrophysics
PI: Don Figer
September 2015 - August 2022

This program will have a profound impact across ground-based and space-based astronomy by dramatically reducing the cost of infrared detectors for existing facilities, as well as the next generation of extremely large telescopes. The project is continuing development of a new material system for use in astronomical infrared array detectors. The devices use HgCdTe grown on Silicon using Molecular Beam Epitaxy. In Phase I of this project, the NSF ATI program funded two cycles of design, fabrication, and testing. The devices made in this phase of the project show that the technology can meet the astronomy requirements pending further development. Testing shows that there are several challenges that prevent the devices in hand from satisfying these requirements. In this second phase, the Center for Detectors is developing a series of devices with improved design and processing. The approach is to reduce the number of material defects while maintaining high short-wavelength quantum efficiency by using proven designs. Given that these previous designs have successfully been used to address the observed non-idealities, it is believed that the new activities will be successful. The work includes: growth of new material using a thick buffer layer design, fabrication of twelve FPAs in two designs, and extensive testing between the fabrications of the two designs.

This project is advancing the knowledge of a material system that has great promise for infrared detector technology. It is also enhancing the capabilities of infrared instrumentation in astronomy by reducing cost and potentially improving performance when compared to what is available with existing technology. The technical approach has great merit because it was developed over the past 15 years and during Phase I of the project. The plan features a tight connection between design at Raytheon Vision Systems (RVS) and testing in the Center for Detectors at the Rochester Institute of Technology, continuing over 15 years of collaboration between RVS and the PI.

PIC: Hybrid Silicon Electronic-Photonic Integrated Neuromorpohic Networks
PI: Stefan Preble
September 2018 - August 2022

The overall goal of this project is to demonstrate hybrid silicon electronic-photonic integrated neuromorphic networks. The proposed paradigm leverages the power of optical interference to realize high performance neuromorphic computing networks. Pho tonic implementations of neural networks brings the inherent advantage that light can easily perform computational tasks that are traditionally challenging to do in electronic-only implementations (e.g. a Fourier transform can be done optically by simply passing light through a lens). However, in order to realize neural networks that significantly improve over today's state-of-art, it is necessary to leverage electronics due to the challenges with realizing photonic memory and amplification. Consequently, we will leverage the advantages of both electronics and photonics to realize neural networks that operate with high-speed and higher performance.

Development of High Efficiency Ultraviolet Optoelectronics: Physics and Novel Device Concepts
PI: Jing Zhang
March 2018 - February 2023

III-nitride-based semiconductor (AlN, GaN, and InN) ultraviolet (UV) optoelectronics have great potential in replacing bulky mercury lamps and excimer lasers attributing to their compact size, lower operating voltage, excellent tunability, higher energy efficiency and longer lifetime. As a result, wide-bandgap AlGaN-based UV light-emitting diodes (LEDs) and laser diodes have attracted significant attentions recently as new UV light sources for various applications such as semiconductor photolithography, resin curing, water and air purification, sterilization, and biological/chemical sensing.

The objective of this project is to develop fundamental physics from the III-Nitride emitters and to propose novel materials and device concepts to address the issues from semiconductor UV LEDs, in order to achieve UV emitters with significantly improved efficiency covering 220 nm ' 300 nm spectral regimes. The research efforts will be divided into three major thrusts: Thrust 1: Development of delta quantum well (QW) UV LEDs covering ~240 nm ' 250 nm; Thrust 2: Exploration of alternative UV active regions: III-Nitrides and beyond; and Thrust 3: Novel UV emitter device concepts.

QLCI-CG: Quantum Photonics Institute
PI: Don Figer
September 2019 - August 2021

Quantum-photonic technologies will form the backbone of future quantum networks, interface/manipulate atomic and solid state platforms, realize sensors and imagers, and process quantum information. Scaling quantum optical systems to many components requires a paradigm-shift from traditional bulk-optics to stable, integrated platforms. Most quantum integrated photonics (QIP) research groups fabricate their devices in-house at academic institutions, but there is increasing interest in instead using foundry-based processes, such as those our NSF Quantum Leap Challenge Institutes Conceptualization Grant (QLCI-CG) team are developing for the American Institute for Manufacturing (AIM) Photonics.

In this successful QLCI CG, the RIT lead team proposed and executed planning activities to allow the team to write a compelling full proposal for a Quantum Photonic Institute in August 2020. This Quantum Photonic Institute would create and use the only U.S-based open-access Quantum Foundry for quantum photonic circuits, including spectral-domain quantum processors, large-scale programmable unitary circuits, high-dimensional quantum light sources, single-photon detectors, and single-photon emitters. The proposed Institute includes a strong workforce and development plan which includes, K-12 and Informal Science Education, recruiting in quantum, expanding a hands-on QIST Education Lab at RIT for undergraduate and graduate students and for on-campus workshops, creating a Women in Quantum community, supporting inclusion and career preparation in QIST graduate education, internship/co-op programs for undergraduate and graduate students, continuing learning for industry professionals, and bringing QIST to all of stem.

Probing the History of Structure Formationthrough Intensity Mapping of the Near Infrared Extragalactic Background Light
PI: Michael Zemcov
September 2017 - September 2021

In 2017, the CfD was selected to receive a NASA Earth and Space Science Fellowship (NESSF), which supports a student's work on the instrument integration and data analysis of CIBER-2. NESSF support enables the student to participate fully in CIBER-2 and gain invaluable experience working on a suborbital project. This experience includes integrating and characterizing the rocket-home instrument at flight facilities; analyzing and interpreting observational data into science findings; and communicating progress to the CIBER-2 collaboration, NASA, and the public.

Development of Quantum Dot Coated Detector Arrays
PI: Zoran Ninkov
July 2019 - June 2021

There are many interesting things to see in the ultraviolet (UV). Lithography for integrated circuit production is exposed with 193 nm light with future, analytical instruments use UV emissions to identify materials, and honeybees' view of flowers include the UV region. Current silicon CMOS or CCD based detectors used in standard digital cameras do a poor job of recording UV images. Switching to exotic materials or polishing the detector until it is so thin that it is flexible and almost transparent may improve the ability to detect UV light. Both of those options are very expensive to fabricate. A different approach is to apply a coating of nanometer-scale materials to the surface of a detector chip to convert the incoming UV light to visible light. Standard detector chips more readily record visible light. We use an inkjet printer to deposit the quantum dots. This research has developed a method of coating detector arrays with nanomaterials and applied it to improve the ability of detectors to record UV and blue light.

On-Chip Quantum Photonic Sensors Using Entagled Photons and Squeezed States
PI: Stefan Preble
October 2019 - September 2021

As a part of this project, we have designed and tested new components that are more efficient and effective at manipulating the physical properties of light. These results have also demonstrated unique applications in quantum information science specifically for processing and sensing. We have also started laying out the design work for a different integrated photonics platform, aluminum nitride, which will be fabricated in a standard CMOS foundry.

Wafer-Level Electronic-Photonic Co-Packaging
PI: Stefan Preble
September 2018 - October 2021

The objective of this program is to develop flexible, low-cost packaging techniques for large scale, integrated optoelectronic systems based on heterogeneously integrated photonic and electronic chips.

Artificial Intelligence RF Photonic Signal Classifier
PI: Stefan Preble
August 2020 - June 2022

The objective of this project will be to prove the feasibility of an RF signal classifier implemented using a photonic neural network. In this project a photonic neural network (PNN) would be developed to classify RF signals a 3-30GHz. The goal is to demonstrate that the PNN can correctly classify signals.

SPEHREx: An All Sky Spectral Survey, Phase B
PI: Michael Zemcov
May 2019 - August 2024

SPHEREx (the Spectro-Photometer for the History of the universe, Epoch of Reionization, and ices Explorer) is a proposed NASA mid-range explorer (MIDEX) mission that will perform an all-sky spectral survey in near-infrared bands. NASA selected SPHEREx for development in February 2019. SPHEREx is designed to map the large-scale structure of galaxies in the universe to shed light on the first instants of the universe, measure the light produced by stars and galaxies over time by using multiple wavelength bands, and investigate how water and biogenic ices influence the formation of planetary systems by studying the abundance and composition of interstellar ices. RIT is responsible for the ongoing development of the data analysis pipeline, with plans for future publications on the analysis methods that Zemcov's team is developing. We recently submitted a paper on advanced point spread function reconstruction techniques for the instrument. Over the past year, the SPHEREx team has remained busy executing the program's Phase B, during which final mission trades are studied and preliminary designs are drawn up. We expect a preliminary design review sometime in autumn 2020, after which we will begin the instrument build phase. SPHEREx is currently scheduled to launch in 2024 and is funded for a full mission through 2027.

Diagnosing, Addressing, and Forecasting CIB Contamination in Spectral Measurements of the Sunyaev Zel'dovich Effect
PI: Michael Zemcov
May 2019 - May 2022

We have updated and improved our analysis of the ICM properties for the cluster RX J1347.5-1145. Significant improvements have been made to the simulated SPIRE map pipeline in order to reduce the error on the amplitude of the Sunyaev-Zeldovich effect. We have shifted to using an older empirical model for generating point sources in our images in order to better fit the high flux end of the map.

Development of 400 nm GaN laser diode
PI: Jing Zhang
March 2021 - February 2022

Escalating trends in global energy consumption mandates like increased national energy independence and mounting alarm regarding anthropogenic climate change, all demand improved sustainable energy solutions. While the theoretical power generation potential of solar photovoltaics (PV) in the United States is greater than the combined potential of all other renewable resources, substantial market penetration of PV and realization of grid-parity have been obstructed by high materials and manufacturing costs, as well as limitations in solar power conversion efficiencies (PCE). A pressing need exists for tandem solar cells utilizing two dissimilar materials (TDM) or more that are capable of PCE values beyond the ~30% Shockley-Queisser limit. In this program, we explore a transformative, bifacial solar cell design that employs arrays of TDM III-V compound semiconductor nanowires in tandem with a thinned, intermediate Si sub-cell. The use of epitaxial nanowire arrays overcomes the lattice matching criteria and enables direct III-V on Si monolithic integration. This design eliminates the need for high-cost wafers, growth of graded buffer layers, and anti-reflection coatings, while permitting ideal solar spectrum matching and capture of albedo radiation. The high risk-high payoff and exploratory research fits the NSF EAGER program, as it involves a radically unconventional approach with transformative potential to enable cost-effective manufacturing of high-efficiency TDM solar cells.

The technical approach of this EAGER project relies on selective-area heteroepitaxy of a GaAsP (1.75 eV) nanowire array on the top surface of a thinned Si (1.1 eV) sub-cell by metal-organic chemical vapor deposition. A bifacial, three dissimilar materials, tandem junction device is formed via monolithic integration of a backside InGaAs (0.5 eV) nanowire array. The vertical nanowires comprising the top- and back-surface arrays contain radially segmented p-i-n junctions serially connected to the central Si sub-cell via epitaxial tunnel junctions. This design enables absorption of broadband incident solar energy as well as albedo radiation. Standard lattice-matching constraints are overcome via strain relaxation along nanowire free surfaces. Therefore, ideal spectral matching is realized without a need for graded buffer layers or dislocation mediation strategies. Use of vertical nanowire arrays with coaxial p-i-n junction geometries permits key advantages, including near-unity absorption of solar irradiance at normal and tilted incidence without the use of anti-reflection coatings, decoupling of photon absorption and carrier collection directions, and dramatic reduction of 95% in epitaxial volumes. Rigorous modeling of device parameters will be iteratively coupled with extensive materials characterization and property correlation experiments for optimization of III-V sub-cell structure on the single nanowire and ensemble array levels. The ultimate target of this work is demonstration of a functional bifacial, three dissimilar materials, nanowire-based tandem junction solar cell with one Sun power conversion efficiency of 30% or better.

Measuring Reionization and the Growth of Molecular Gas with TIME
PI: Michael Zemcov
September 2019 - August 2022

While waiting for the TIME instrument's second deployment, the team has focused on improving the quicklook data analysis infrastructure and simulated data pipeline. Work continued on an advanced biasing technique to quickly determine the state of almost 2000 TES bolometers, and then electrically bias them for optimal detection of sub-mm photons. This involved writing a script for determining the optimal bias during lab conditions, and then adjusting this bias for changes in loading due to atmosphere and astrophysical sources. The incremental biasing technique is accomplished by choosing the most conservative bias and slowly stepping down until a maximum number of detectors can be reached. Biasing too low renders the detectors insensitive to on sky photons. This process is being automated for quick calibration of the instrument between science observations.

Updates were also made to the map making code which is responsible for converting raw detector timestreams into science output. To test the systematics and biases introduced into the data from the analysis pipeline, the team helped create simulated science data. TIME collaborators created artificial science sources, mimicking some of the planets observed in the last engineering run, and added atmospheric noise realizations. The team provided a simulated telescope scanning script which sampled this data in the appropriate sky configuration and output realistic detector timestreams. After these are run through the map making pipeline, the difference between the output maps and the input simulated sources should provide correctional factors used in the real analysis.

Development of an On-Chip Integrated Spectrometer for Far-IR Astrophysics
PI: Michael Zemcov
July 2020 - July 2022

The primary objective is the production of an integrated on-chip spectrometer prototype operable at 150 micron wavelength. The spectrometer will be integrated with a kinetic inductance device (KID) detector array on the same chip, integrating the light dispersion and detection on a single Si wafer. We target a spectral resolution of R=I00, and plan to demonstrate at least 8 bands around the central wavelength. Spectral testing of the spectrometer prototype will be carried out using a compact Fourier Transform Spectrometer (FTS) that is being developed at RIT.

The FTS consists of a simple interferometer fed by a hot or cold thermal source, with path length difference adjusted using a linear actuator. The FTS is designed to be operated within a small cryostat to reduce stray radiation loading, and coupled either directly or via a small vacuum window to match that of the test bed. Varying the path length introduces a changing pattern of interference fringes at the detector under test, which will be analyzed to reconstruct the detector response as a function of frequency. The output of the FTS itself will be characterized using a laboratory bolometer system. Currently a warm version of the FTS system is being tested to aid in the development of software and integration of the final cold design. Once warm testing is finished we will modify this existing system for cryogenic operation.

The Development of Digital Micromirror Devices for use in Space
PI: Zoran Ninkov
May 2014 - May 2018

This project is developing a commercially-available Digital Micromirror Device (DMD) with an ultraviolet transparent window suitable for use in a multi-object spectrograph (MOS) in a future NASA Explorer Mission. A large spectroscopic survey requires a MOS capable of recording the spectra of hundreds of galaxies in a single exposure. The MOS must have adjustable slits to eliminate confusion with nearby sources and to block out unwanted zodiacal background, which would otherwise swamp the light from these faint galaxies. The MOS should have access to the far-ultraviolet (120-200 nm) radiation emitted by a z~1 galaxy because this spectral region has a rich set of diagnostics of stars, gas, and dust in the galaxy. Access to the blue-red spectral regions (200-800 nm) is also essential for determining the precise redshift of a galaxy, its stellar mass, abundances of the elements, and for characterizing dust extinction. Because the light from a z~1 galaxy is redshifted before reaching us, a large spectroscopic survey should be sensitive over the spectral interval, 200-1600 nm.

Integrated Quantum Photonics for Photon-Ion Entanglement
PI: Stefan Preble
October 2014 - September 2018

The primary objective of this project is the realization of an integrated photonics platform compatible with photon-ion entanglement. The platform will consist of photon sources and entangling circuits that interface with the visible/UV wavelengths of ion (such as Yb+, Ca+, Be+, Mg+, Sr+, Ba+, Zn+, Hg+ and Cd+) transitions. The challenge with realizing such a platform is that integrated photonic chips are not well developed at visible wavelengths because of the traditional focus on telecom wavelength compatibility. We are developing a platform that does operate at short wavelengths by using Aluminum Nitride (AlN), which is a large bandgap semiconductor that is transparent to the deep-UV. In parallel, we are leveraging our successes in quantum integrated photonics in telecom-compatible platforms, particularly silicon photonics. This will allow rapid validation of high performance photon sources, entanglement circuits and quantum sensors. These circuits will then be transitioned to the new visible/UV platform, or interfaced with ions directly by using frequency conversion

Wideband Quantum Photonic Integrated Circuits for Highly Non-degenerate Photon Pair Entanglement
PI: Stefan Preble
June 2020 - November 2020

The overall goal of this project is to develop and integrate Si photonics based wideband Quantum Photonic Integrated Circuits (Q-PICs) efficiently and robustly with highly nonlinear polarization entangled photon pair generating waveguides. The wideband Q-PICs can provide spectral filtering, timing compensation and low-loss routing to on-chip photonic gates for quantum processing. This project demonstrated the feasibility of maintaining robust, high efficiency coupling between an arrayed highly non-degenerate photon pair source and a hybrid Si/SiN Q-PIC. The key innovation in this effort is butt coupling a periodically poled Potassium Titanyl Phosphate (KTP) waveguide-based wavelength division Multiplexer (WDM) to the hybrid Q-PIC, which is fabricated with both Si and SiN waveguides for low loss transmission of the highly non-degenerate wavelengths (1550/810). High photon pair generation was demonstrated with high efficiency coupling to the Q-PIC.

RIT/L3Harris Quantum Information Collaboration
PI: Stefan Preble
Yearly

L3Harris has partnered with RIT on experiments and analysis focused on quantum information processing for communication, sensing, and computing. The exploratory partnership provides L3Harris access to FPI's laboratory space and researchers and students.

Analysis of the Optical Properties of Digital Micromirror Devices in the Ultraviolet Wavelength Regime
PI: Zoran Ninkov
April 2020 - December 2021

RIT proposes to support the efforts "The Space Telescope Ultraviolet Facility (The STUF)" project led by STScl PI Mario Gennaro. RIT will provide digital micromirror devices (DMDs) with standard protective windows replaced by ultraviolet transparent windows appropriate for studies of DMDs optical properties in the ultraviolet regime. Our proposal includes also a request to support a student from RIT for a two-year period.

Bifacial III-V Nanowire Array on Si Tandem Junctions Solar Cells
PI: Parsian Mohseni
May 2017 - October 2020

Escalating trends in global energy consumption, mandates for increased national energy independence, and mounting alarm regarding anthropogenic climate change all demand improved sustainable energy solutions. While the theoretical power generation potential of solar photovoltaics (PV) in the United States is greater than the combined potential of all other renewable resources, substantial market penetration of PV sand realization of grid-parity have been obstructed by high materials and manufacturing costs, as well as limitations in solar power conversion efficiencies (PCE). A pressing need exists for tandem solar cells utilizing two dissimilar materials (TDM) or more that are capable of PCE values beyond the ~30% Shockley-Queisser limit. In this program we explore a transformative, bifacial solar cell design that employs arrays of TDM III-V compound semiconductor nanowires in tandem with a thinned, intermediate Si sub-cell. The use of epitaxial nanowire arrays overcomes the lattice matching criteria and enables direct III-V on Si monolithic integration. This design eliminates the need for high-cost wafers, growth of graded buffer layers, and anti-reflection coatings, while permitting ideal solar spectrum matching and capture of albedo radiation. The high risk-high payoff and exploratory research fits the NSF EAGER program, as it involves a radically unconventional approach with transformative potential to enable cost-effective manufacturing of high-efficiency TDM solar cells.

Multi-Color Anisotropy Measurements of Cosmic Near-Infrared Extragalactic Background Light with CIBER2
PI: Michael Zemcov
May 2016 - July 2019

The Rochester Institute of Technology team is responsible for the delivery of a cryogenically-operable star tracking camera for attitude control of the CIBER-2 payload. RIT is building, testing, and delivering this camera to Caltech for integration into the full experiment by the beginning of Year 2. RIT is also responsible for delivering the associated documentation and interface information to both Caltech and NASA by the end of Year 2. The RIT team is also responsible for assisting with: (1) overall instrument design; (2) integration of the payload system; (3) laboratory testing and characterization; (4) flight planning and logistical requirements; (5) deployment and flight efforts; (6) data reduction and calibration; and (7) science extraction.

Understanding and Engineering Valence Band Structures of III-Nitride Semiconductors for High-Efficiency Ultraviolet Lasers and Emitters
PI: Jing Zhang
June 2016 - November 2020

The objective of this project is to advance the fundamental understanding of the physics of GaN-based active regions in nitride heterostructures in order to enable high-efficiency electrically-injected UV lasers and emitters with wavelengths ranging from 220 nm to 300 nm at room temperature. Particularly, this research focuses on the fundamental understanding of the valence band structure of lll-Nitride wide bandgap gain active region, and develop promising solutions for nanostructured quantum wells and the fabrication approach of large area GaN-based UV laser arrays. Those lasers would be a promising candidate for various naval applications in sensing and communication.

Quantum Optical Semiconductor Chip and its Application to Quantum communication
PI: Stefan Preble
May 2020 - October 2020

Develop a quantum optical semiconductor chip and demonstrate its application to efficient photonic entanglement, efficient logic gates such as Hadamard and CNOT, and quantum communication protocols through fiber optical channels.

On-Chip Quantum Photonic Sensors Using Entangled Photons and Squeezed States
PI: Stefan Preble
October 2019 - September 2021

As a part of this project, we have designed and tested new components that are more efficient and effective at manipulating the physical properties of light. These results have also demonstrated unique applications in quantum information science specifically for processing and sensing. We have also started laying out the design work for a different integrated photonics platform, aluminum nitride, which will be fabricated in a standard CMOS foundry.

TDM Solar Cells: Bifacial III-V Nanowire Array on Si Tandem Junctions Solar Cells
PI: Parsian Mohseni
May 2017 - October 2020

Escalating trends in global energy consumption mandates like increased national energy independence and mounting alarm regarding anthropogenic climate change, all demand improved sustainable energy solutions. While the theoretical power generation potential of solar photovoltaics (PV) in the United States is greater than the combined potential of all other renewable resources, substantial market penetration of PV and realization of grid-parity have been obstructed by high materials and manufacturing costs, as well as limitations in solar power conversion efficiencies (PCE). A pressing need exists for tandem solar cells utilizing two dissimilar materials (TDM) or more that are capable of PCE values beyond the ~30% Shockley-Queisser limit. In this program, we explore a transformative, bifacial solar cell design that employs arrays of TDM III-V compound semiconductor nanowires in tandem with a thinned, intermediate Si sub-cell. The use of epitaxial nanowire arrays overcomes the lattice matching criteria and enables direct III-V on Si monolithic integration. This design eliminates the need for high-cost wafers, growth of graded buffer layers, and anti-reflection coatings, while permitting ideal solar spectrum matching and capture of albedo radiation. The high risk-high payoff and exploratory research fits the NSF EAGER program, as it involves a radically unconventional approach with transformative potential to enable cost-effective manufacturing of high-efficiency TDM solar cells.

The technical approach of this EAGER project relies on selective-area heteroepitaxy of a GaAsP (1.75 eV) nanowire array on the top surface of a thinned Si (1.1 eV) sub-cell by metal-organic chemical vapor deposition. A bifacial, three dissimilar materials, tandem junction device is formed via monolithic integration of a backside InGaAs (0.5 eV) nanowire array. The vertical nanowires comprising the top- and back-surface arrays contain radially segmented p-i-n junctions serially connected to the central Si sub-cell via epitaxial tunnel junctions. This design enables absorption of broadband incident solar energy as well as albedo radiation. Standard lattice-matching constraints are overcome via strain relaxation along nanowire free surfaces. Therefore, ideal spectral matching is realized without a need for graded buffer layers or dislocation mediation strategies. Use of vertical nanowire arrays with coaxial p-i-n junction geometries permits key advantages, including near-unity absorption of solar irradiance at normal and tilted incidence without the use of anti-reflection coatings, decoupling of photon absorption and carrier collection directions, and dramatic reduction of 95% in epitaxial volumes. Rigorous modeling of device parameters will be iteratively coupled with extensive materials characterization and property correlation experiments for optimization of III-V sub-cell structure on the single nanowire and ensemble array levels. The ultimate target of this work is demonstration of a functional bifacial, three dissimilar materials, nanowire-based tandem junction solar cell with one Sun power conversion efficiency of 30% or better.


Past Projects

AIM Photonics TAP004 and TAP005 (Test Assembly and Packaging Hub Planning)
PI: Stefan Preble
October 2015 - June 2017

This project enables the technologies being used at AIM Photonics testing assembly and packaging (TAP) facility in Rochester, NY. The organization of the TAP hub project is along the following technical categories of Optical I/O, Testing, Metrology, and Reliability. The hub is equipped for 2.5 electronic/photonic packaging, attach and align tools for fibers and fiber/waveguide arrays, functional testing equipment, as well as a full line of metrology tools. The project emphasizes the most significant gaps in the manufacturing of Photonic Integrated Circuit (PIC)-enabled systems by enabling and ensuring access to standardized package designs, integrating the photonic, electronic, and physical designs, ensuring that metrology tools are available to test the physical integrity of the packages, and providing functional testing for digital, analog, and sensor-based photonic systems. The current activities are concentrating on establishing processes, and packaging design and test support for AIM Photonics members through the Rochester Hub. The project also produces AIM Photonics Test, Assembly and Packaging Guide, which is included in the AIM Photonics Process Design Kit (PDK) releases.

New Infrared Detectors for Astrophysics
PI: Don Figer
June 2012 - May 2017

This project aims to develop infrared detectors that use HgCdTe material grown on silicon substrates (MCT/Si). Traditionally, manufacturers use CdZnTe (CZT) substrates because they have the same lattice spacing as MCT, providing fewer possibilities for undesired energy states where atoms in the lattice do not meet. Unfortunately, CZT substrates are expensive and come in small sizes. Both factors increase the cost of MCT detectors. In contrast, Si wafers are widely available and in large sizes. MCT/Si technology will dramatically reduce the cost and size constraints imposed by CZT substrates used in sensors for ground- and space-based astronomy missions.

Previous work on this project included targeted design changes to MCT/Si detectors that improved operation. The CfD tested multiple detector lots designed and fabricated by Raytheon Vision Systems (RVS). As an example of a successful design change, RVS excluded epoxy backfilling from the thinning process during detector substrate removal. This decreased interpixel capacitance, or an undesired transfer of charge between pixels, caused by the epoxy filling.

Changes in the lot of detectors we received from RVS in late 2018 targeted improving dark current. Dark current measures signal when there is no illumination on the detector. As temperature increases, some lattice vibrations are larger than the bandgap energy of the detector material and cause an electronic transition to the conduction band, resulting in a signal. We take many long exposures with no illumination to measure dark current. F13 has a large tail in the dark current histogram, and only about 65% of all pixels have a dark current below 0.6 e'/s. We hypothesized that mismatches in the lattice of the HgCdTe and Si substrate formed coupled dislocations, resulting in higher dark current.

Developing THz Detector Technology for Inspection Applications
PI: Zoran Ninkov
July 2017 - June 2018

The terahertz frequency (THz) region provides a means of using non-ionizing radiation to perform a variety of non-invasive sensing tasks. Commercial cameras systems are available that utilize microbolometer or pyroelectric detectors to detect THz wavelength radiation, but these devices lack sensitivity, stability, or readout speed. RIT and its collaborators at the University of Rochester and Harris Corporation are developing a room-temperature imaging THz frequency detector using Si-MOSFET (Silicon Metal Oxide Semiconductor Field Effect Transistor) CMOS devices. The devices are implemented into a focal plane imaging array for use in many applications, such as transmission or penetration imaging and spectroscopy. Technology for THz detection is often extremely costly, due to either expensive detector materials or cryogenic cooling systems. The devices tested here, however, are low-cost due to the use of conventional room temperature silicon CMOS technology. The devices operate from 170 to 250 GHz, with an additional detector design fabricated for 30 THz (10 'm wavelength).

Imaging Polarimetry
PI: Zoran Ninkov

Imaging polarimeters utilizing the division-of-focal technique present unique challenges during the data reduction process. Because an image is formed directly on the polarizing optic, each pixel 'sees' a different part of the scene; this problem is analogous to the challenges in color restoration that arise with the use of Bayer filters.

Although polarization is an inherent property of light, the vast majority of light sensors (including bolometers, semiconductor devices, and photographic emulsions) are only able to measure the intensity of incident radiation. A polarimeter measures the polarization of the electromagnetic field by converting differences in polarization into differences in intensity. The microgrid polarizer array (MGPA) divides the focal plane into an array of superpixels. Each sub-pixel samples the electric field along a different direction, polarizing the light that passes through it and modulating the intensity according to the polarization of the light and the orientation of the polarizer. We are actively looking at techniques for hybridizing microgrid polarizer arrays to commercial CID, CCD, and CMOS arrays.

Cosmic Radiation Damaged Image Repair project (CRDIR)
Advisor: Don Figer

RIT has embarked on the Cosmic Radiation Damaged Image Repair project (CRDIR) involving Dr. Donald Pettit, NASA Astronaut & International Space Station astrophotographer. This project is being conducted by graduate and undergraduate student researchers under the guidance of Dr. Donald Figer, Director of CfD.

Students have a unique opportunity to communicate with an active American astronaut in the process of solving a significant image processing issue. The scientific process these students follow toward a solution provide valuable experience that these students will carry with them in their professional lives.

RIT is providing a sophisticated 'image enhancement' software program which specifically addresses degraded images taken by astronauts 'on orbit', extending the useful lives of cameras, and in many cases making unacceptable 'noisy' images visually acceptable.

AIM Academy Photonic Integrated Circuit Design and Test Education Curricula
PI: Stefan Preble
January 2019 - December 2020

This project's long-term objective is the creation of a workforce of proficient integrated photonic circuit designers. There is a clear industry need for designers that are able to utilize Electronic Photonic Design Automation (EPDA) methodologies to effectively design functional photonic-electronic circuitry to drive the integrated photonics industry into the future. The primary goal of this project is to meet this need with the creation of integrated photonic circuit design/test content to enable educators to teach students and industrial practitioners the principles, methodologies and practical knowledge of integrated photonic circuit design.

MRI: Acquisition of an Inductively Coupled Plasma Reactive-Ion Etching System for Research and Education in Nanophotonics, Nanoelectronics and Nano-Bio Devices
PI: Jing Zhang
September 2016 - August 2017

This Major Research Instrumentation (MRI) funding is supporting the acquisition of an inductively coupled plasma reactive-ion etching (ICP-RIE) system to enable fundamental research and education in nanophotonics, nanoelectronics and nano-bio devices. The objective of this MRI acquisition is to facilitate new and existing multidisciplinary research in science and engineering, enable educational curriculum development, and promote outreach activities at Rochester Institute of Technology (RIT). The ICP-RIE system has the capability for photonic, electronic and bio device fabrication that does not exist presently at RIT and Rochester region.

The ICP-RIE system provides dry etching capability for various material systems such as compound semiconductors, dielectric materials, and metals with fast etching rate, well-controlled selectivity, and promising uniformity. The instrument is essential to enable fundamental research and education on III-Nitride based light emitting diodes (LEDs) and lasers, seamless integration of robust and low-powered III-V quantum dot (QD) lasers with silicon photonics, III-V tunneling field effect transistor, memory devices for computing, QD and nanowire photovoltaics, III-Nitride photodetectors for inertial confinement fusion research, nanoplasmonic devices, and nan-bio devices for efficient biomolecule transfer. The instrument will be the first ICP dry etcher tool at RIT, which will be shared by research groups across all disciplines in science and engineering with students trained from Microsystems Engineering Ph.D. program and Ph.D. in Engineering program. The tool will also be shared by external research groups in Rochester region to enhance research and collaborations between RIT and other colleges, national labs, and small businesses in the region.

The ICP-RIE system will be designated as a shared user facility, available to new curriculum and lab section development on device fabrications for both undergraduate and graduate students at RIT, whom can be trained for next-generation scientists and engineers. The fabrication capability provided by the proposed instrument benefits curriculum development at RIT for several fundamental courses and lab sections focused on nanofabrication and semiconductor devices. Demonstration experiments on photonic and electronic devices can also be designed to K-12 students and teachers through RIT outreach activities by the use of the dry etcher, which can stimulate K-12 students' interest to pursue science, technology, engineering, and mathematics (STEM) disciplines in the future. Connectivity with such demonstration experiments will also be promoted to train existing women and underrepresented minority students at RIT.

Quantum Optical Resonators: a building block for quantum computing and sensing systems
PI:Stefan Preble
August 2014 - July 2018

The overall goal of this project is to experimentally demonstrate the quantum optical response of ring resonators and use them as a robust building block for quantum information processing. We have shown that ring resonators operating in the quantum regime exhibit a resonant response that depends on the photon state. Unlike beam splitters, which operate with maximum fidelity with only one set of parameters, the unique passive feedback in ring resonators ensures high fidelity quantum interference over effectively an infinite device parameter space. The devices compact size and ability to be reconfigured dynamically with low energy requirements ensures that ring resonators are the ideal building block for realizing complex quantum optical circuits.

Imaging Polarimetry with Microgrid Polarizers
PI:Zoran Ninkov
September 2012 - December 2015

Polarization is an intrinsic property of light, like frequency or coherence. Humans have long benefited from our ability to distinguish light of different frequency based on its color. However, our eyes are not sensitive to the polarization of light. Devices to measure polarization are relatively rare and expertise in polarimetry even more so. Polarization sensors based on micropolarizer arrays appear to be the first devices capable of bringing polarimetric capability to a wide range of applications. Whereas previous polarimeters were built to perform very specific measurements, the same micropolarizer-based camera can be used on a telescope, a microscope, or with a conventional camera lens.

THz Modeling and Testing
PI:Zoran Ninkov
July 2016 - June 2017

A group consisting of Harris engineers, RIT scientists, University of Rochester engineers and scientists designed and manufactured a room temperature silicon Complementary metal'oxide'semiconductor (CMOS) imager for terahertz (THz) frequencies using metal-oxide semiconductor field effect transistors (MOSFETs). THz frequencies have been largely unexplored due to high absorption within water, however there has been an increase in interest with the rise in high-altitude and space-based telescopes. Emission lines in spectra within the THz regime exhibit cool molecular gas which traces protoplanetary disks and star formation rates within galaxies. This technology also has other applications within the medical and security fields because of the nonionizing, non-harmful nature of THz radiation.

Engineering Verification Test (EVT) Station
Stefan Preble

A collaborative effort between Columbia University, RIT, and Precision Optical Transceivers, this project will develop testing capabilities for the Testing Assembly and Packaging (TAP) Hub that AIM Photonics is building in downtown Rochester, NY. The EVT is a generalized testing tool for validating functionality and performance specifications of integrated silicon circuits, such as optical switches, transceivers, photonic biosensors, lasers, etc. It is a crucial element of AIM Photonics and represents a much-anticipated capability that customers will use to prove the validity of their circuit designs. The EVT system will first be used for the testing of a C form-factor pluggable (CFP) based package that is currently being developed at Columbia University for the purpose of controlling complex photonic integrated circuits (PICs), including high speed transceivers and photonic switch fabrics. The EVT will later be able to test a quad small form-factor pluggable (QSFP) based package that is being developed by Precision Optical Transceivers. As the project proceeds, work will continue to be done to create software for functional and performance tests in order to validate the EVT station for photonic switches and more.

Concept Study Report Preparation for SPHEREx MIDEX Phase A
PI: Michael Zemcov
February 2018 - September 2018

SPHEREx is a planned NASA mid-range explorer (MID EX) that will perform an all-sky spectral survey of the in near-infrared bands. SPHEREx was recently selected for a Phase A study, and work is required to refine the instrument concept before a concept study report is due to NASA in mid-2018. This program funds activity at RIT to help refine details of the instrument, observation strategy, and to support publishing them as reports for NASA and the community.

SOAR/SAM Multi Object Spectrograph (SAMOS)
PI: Zoran Ninkov
September 2016 - August 2021

RIT is collaborating in a project to build the SOAR Multi-Object-Spectrograph (SAMOS) for the SOAR 4.1 m telescope. SAMOS takes advantage of the Ground Layer Adaptive Optics laser guided system that routinely delivers exceptional image quality at visible wavelengths over a large field. There is great demand for a facility capable of efficiently performing spectroscopic studies of crowded fields, e.g., the Magellanic Clouds, globular dusters, the galactic bulge, and galaxy clusters. SAMOS can take hundreds of spectra in parallel over the full corrected field using a commercial Digital Micromirror Device (DMD) as a slit selector mechanism.

Cosmic Dawn Intensity Mapper
PI: Michael Zemcov
April 2017 - August 2018

The NASA Probe-Class Mission Concept Cosmic Dawn Intensity Mapper (CDIM) is designed to make pioneering observations of the Lyman-alpha, H-alpha and other spectral lines of interest throughout the history of the cosmos. Capable of spectro-imaging observations between 0.7 to 7 'm in the near-Infrared, CDIM will help move the astronomical community from broad-band astronomical imaging to low-resolution (R=300-400) 3D spectro-imaging of the universe to perform the science of the 2030s. In this program, we are performing a mission concept study that will be submitted to both NASA and the US astronomical community in preparation for the 2020 Astronomy Decadal Report. The RIT team lead by Dr. Michael Zemcov is performing initial engineering and instrument design work in support of detailed science requirements being derived by the science team. This work has led to a fully functional instrument sensitivity calculator, and a complete mission initial engineering study performed by an RIT Engineering MS student.

Selective Area Epitaxy of III-V Nanocrystals on Graphene and MoS2 for Flexible Optoelectronics Application
PI: Parsian Mohseni
May 2016 - August 2017

Atomically-thin, two-dimensional nanomaterials such as single-layer graphene (SLG) and monolayer molybdenum disulfide (MoS2) have emerged as essential building blocks that can enable the development of a widely encompassing class of next-generation nanoelectronic devices. However, these monolayer materials have a critical drawback for applications in optoelectronic, in that they are either inherently incapable (i.e., SLG) of, or are fundamentally inefficient (i.e., MoS2) in, absorbing and emitting light. The purpose of this project is to overcome this limitation through the monolithic integration of highly optically efficient 111-V semiconductor nanostructures with SLG and MoS2 by selective area epitaxial (SAE) crystal growth. This effort aims to combine the characteristic benefits of monolayer materials and 111-V nanocrystals through the synthesis of novel types of hybrid nanostructures. The correlation of extensive structural and optical characterization experiments enables the optimization of SAE growth parameters, and subsequently enable the development of low-cost and high-efficiency flexible light emitting diodes and photodetectors.

A Cryogenic Optical Camera for Attitude Control of Low-Temperature Sub-Orbital Payloads
PI: Michael Zemcov
May 2016 - May 2019

CCDs have been the dominant optical-wavelength detector architecture for high-end optical imaging applications for decades. However, CCDs are inoperable below 120 K due to electron freeze-out effects, prohibiting their use in space exploration applications requiring cryogenic temperatures. Megapixel CMOS devices are known to work at temperatures as low as 10 K, suggesting that imaging devices based on this technology would operate in cryogenic environments without requiring active heating. In this program, we take the first step to maturing this technology for flight applications in the cryogenic regime by developing and flying an attitude-sensing camera employing a low noise, high quantum efficiency cryogenic CMOS detector. By implementing an alternative imaging technology, we address NASA's major objective to 'transform NASA missions and advance the Nation's capabilities by maturing crosscutting and innovative space technologies.' This technology enables instruments ranging from actively cooled star trackers for sounding rockets to low-temperature deep space cameras.

Development of the Next Large Space Telescope
Co-Chair: Don Figer

CfD Director Figer is Co-chairing a NASA technology working group with Eric Schindhelm (Ball Aerospace & Technologies Corp.) to assess the current state of the art in detectors for ultraviolet, optical, and infrared wavelengths. This activity is a precursor to the plans for the further development of competing technologies to fly on the next large space telescope after the James Webb Space Telescope (JWST). The new telescope has a notional design and is generically being called the Large Ultraviolet Optical Infrared Survey (LUVOIR) telescope. Just as with previous NASA missions, this somewhat awkward name will be likely be replaced with a name that memorializes a prominent figure in the advancement of science.

The LUVOIR point design considers the use of a large (8-12 m) primary mirror that capitalizes on the emerging heavy lift capabilities, such as the Big Falcon Rocket (BFR) to be made by SpaceX and the Space Launch System (SLS) being developed by NASA and partners. Just like JWST, the telescope will be launched in a furled configuration to be expanded and phased on orbit.

The detector technology working group solicited information concerning the technology readiness level of approximately a dozen competing detector types that could fly on LUVOIR, either in the wide area imaging camera or the coronagraph instrument. For most science applications on the proposed telescope, detectors will need to have very low noise. In fact, for the goal of measuring the atmospheres of exoplanets, the detectors will need to have single photon sensitivity.

Rare Massive Stars Near the Galactic Center
Collaborator: Don Figer

CfD Director Figer, and collaborators, identified more massive stars near the Galactic center (GC). Some of these stars are of the rarest types, representing exotic evolutionary stages of the most massive stars.

In one study, the team validated a hypothesis that they made in the late 1990's that the enigmatic red stars in the Quintuplet Cluster are of the rare late-type carbon Wolf-Rayet type. There are only a few hundred such stars, out of a few hundred billion, in the Galaxy. These types of stars are evolved forms of stars that have approximately a hundred solar masses of material. To find five such stars in one cluster is unprecedented.

In a paper in the Astrophysical Journal, we reported the detection of a number of emission lines in the 1.0'2.4 'm spectra of four of the five of the Quintuplet stars. Spectroscopy of the central stars of these objects is hampered not only by the large interstellar extinction that obscures all of the objects in the GC, but also by the large amounts of warm circumstellar dust surrounding each of the five stars. The pinwheel morphologies of the dust observed previously around two of them are indicative of Wolf'Rayet colliding wind binaries; however, infrared spectra of each of the five have until now revealed only dust continua steeply rising to long wavelengths and absorption lines and bands from interstellar gas and dust. The emission lines detected, from ionized carbon and from helium, are broad and confirm that the objects are dusty late-type carbon Wolf'Rayet stars.

In another study, published in Astronomy and Astrophysics, CfD Director Figer was part of a team that reported a new stellar census of massive stars in the Quintuplet Cluster.

The Quintuplet is one of the most massive young clusters in the Galaxy and thus holds the prospect of constraining stellar formation and evolution in extreme environments. Current observations suggest that it comprises a remarkably diverse population of very high-mass stars that appears difficult to reconcile with an instantaneous star-formation event. The team used new, and existing, observations of stars in the cluster to better understand the origin and nature of the cluster, including from the Near Infrared Camera and the infrared channel of the Wide Field Camera 3, both on the Hubble Space Telescope, and SINFONI and KMOS on the Very Large Telescope. In all, the team observed approximately 100 cluster members.

Spectroscopy of the cluster members reveals that the Quintuplet is more homogeneous than previously expected. All supergiants are classified as either O7-8 Ia or O9-B0 Ia, with only one object of earlier (O5 I-III) spectral type. These stars form a smooth morphological sequence with a cohort of seven early-B hypergiants and six luminous blue variables and WN9-11h stars; these comprise the richest population of such stars of any stellar aggregate known. In parallel to these, we identify a smaller population of late-O hypergiants and spectroscopically similar WN8-9ha stars. No further H-free WC or WN stars are identified, leaving an unexpectedly extreme ratio of 13:1 for this population.

Photometric data reveals a subset of the O9-B0 supergiants to be unexpectedly faint, suggesting they are both less massive and older than the greater cluster population. Finally, no main sequence objects were identifiable. Due to uncertainties in the correct extinction law, it was not possible to quantitatively determine a cluster age via isochrone fitting.

Fortuitously, we find an impressive coincidence between the properties of cluster members preceding the hydrogen-free WR phase and the evolutionary predictions for a single, non-rotating 60 MSun star; in turn this implies an age of ~3.0 - 3.6 Myr for the Quintuplet. Neither the late O-hypergiants, nor the low luminosity supergiants, are predicted by such a path; we suggest that the former result from either rapid rotators are the products of binary driven mass-stripping, while the latter may be interlopers. The hydrogen-free WRs must evolve from stars with an initial mass in excess of 60 MSun, but it appears difficult to reconcile their observational properties with theoretical expectations. This is important since one would expect the most massive stars within the Quintuplet to be undergoing core-collapse/SNe at this time; since the WRs represent an evolutionary phase directly preceding this event their physical properties are crucial to understanding both this process and the nature of the resultant relativistic remnant. As such, the Quintuplet looks set to provide unique observational constraints on the evolution and death of the most massive stars forming in the local, high-metallicity Universe.

Development of Si-MOSFET CMOS Technology for Terahertz Detection
PI:Stefan Preble

RIT is developing a silicon MOSFET CMOS imager to detect terahertz (THz) frequencies in a collaboration with the Center for Emerging and Innovative Sciences (CEIS) at the University of Rochester and Exelis Geospatial Systems. Creating an asymmetrical design within the FETs, increases the THz response. The current device being tested was designed with 15 individual test transistors with varying design dimensions and antennas along with an array of transistors for an imager. These test structures are being evaluated at RIT to determine the best design for terahertz detection for future imager designs. An advantage of this detector technology is that these MOSFETs do not have to be cooled to extreme temperatures like microbolometers. This project's goal is to advance knowledge of the detection mechanism, lead to the creation of an integrated imaging system, and has many different applications.

THz frequencies have been largely unexplored due to high absorption within water, however there has been an increase in interest with the rise in high-altitude and space-based telescopes. Emission lines in spectra within the THz regime exhibit cool molecular gas which traces protoplanetary disks and star formation rates within galaxies. This technology also has other applications within the medical and security fields because of the non ionizing, non-harmful nature of THz radiation.

Characterization of Inter-Pixel Capacitive Coupling in Hybridized HgCdTe Arrays
PI:Zoran Ninkov

Inter-Pixel Capacitance (IPC) is a mechanism for deterministic electronic cross talk that results from coupling fields between adjacent pixels as a signal is collected and stored. Simulation of small arrays from first principles using software which simultaneously solves Poisson's equation and the Drift Diffusion equations allows for characterization of this coupling across a broad range of design parameters as well as across various environment parameters. Due to the deterministic nature of this cross-talk characterization results in correction.

This project is currently working on characterization of HgCdTe arrays hybridized using indium bumps to h4RG readout circuits akin to those to be used in the James Webb Space Telescope's (JWST) NIRcam. Successful characterization across environment parameters will result in an increase in final image quality from JWST's NIRcam and any device using a similar detector while also introducing new design considerations for future generations of sensor.

MacEtch of III-V Compounds Using Alternative Catalysts
PI: Parsian Mohseni

Metal-assisted chemical etching (MacEtch) is an anisotropic, solution-based nanofabrication process that combines the benefits of conventional wet-etching and plasma-based ion etching. The MacEtch process relies on site-specific, catalytic oxidation of a semiconductor surface by a patterned noble metal layer, followed by preferential dissolution of the selectively oxidized regions. Continuous repetition of oxidation-dissolution cycles in a single MacEtch bath results in the metal layer sinking into the semiconductor such that vertical nanostructures are left in the path of the metal layer, having geometries that are complementary to the geometry of the patterned metal. In the EINS lab, we are interested in exploring the fabrication of III-V semiconductor nanostructures using non-conventional metallic catalysts composed of carbon-nanotubes and graphene. In this manner we define novel nanofabrication paradigms that enable low-cost and clean alternatives to conventional ion-based etching procedures, offering high-aspect ratio features with atomically-abrupt sidewall termination. Novel device applications in high-efficiency solid-state lighting and tri-gated nanofin-based field effect transistors have already been demonstrated using on MacEtch fabrication.

Selective Area Epitaxy on Foreign Substrates
PI:Parsian Mohseni

The growth of various nanostructures, including nanowires and nanofins, by metal-organic chemical vapor deposition (MOCVD) is investigated through a unique crystal synthesis process known as selective area epitaxy (SAE). The SAE method relies on an oxide template with predefined windows that specify the location of preferential epitaxial atomic assembly. Growth rate enhancement, as defined by the oxide template, allows for the controlled epitaxy of arrays of vertical, III-V compound semiconductor nanostructures without the use of foreign catalytic or seeding agents. Based on the SAE technique, the EINS lab has demonstrated growth of InAs, InGaAs, GaAs, GaAsP, and GaP nanowire and nanofin arrays on Si substrates with 100% yield over large, wafer-scale areas. Our current projects aim to understand the growth kinetics of III-V nanosystems interfaced with Si and 2-dimensional nanomaterials such as graphene and monolayer transition metal dichalcogenides; to characterize the novel material properties offered by these hybrid nanosystems; and to demonstrate their utility in innovative photovoltaics and optoelectronics solutions.

Enhancing the UV/VUV Sensitivity of CMOS Image Sensors
PI: Zoran Ninkov
July 2016 - June 2017

Charge-coupled devices (CCDs) and CMOS arrays have limitations in spectral sensitivity as delivered from the foundry. The front-side gate structure of a CCD is absorptive at ultraviolet (UV) wavelengths. For high efficiency, CCDs are back illuminated, which is expensive to do, and unfortunately the Si substrate is highly reflective. Additionally, UV photons have a very short absorption length in silicon. The electron'hole pairs produced by the photon interaction are trapped at the back surface and therefore never reach the accumulation phase gate. These issues have resulted in difficulty in producing efficient CCD-based UV/Far UV (FUV) detectors. Delta doped back illuminated CCDs are the best solution to this problem. Anti-reflection (AR) coating the CCD is difficult in this spectral region as the coatings available only provide improvement over a narrow spectral region. This is especially concerning for application in UV/FUV spectroscopy where a wide spectral range needs to be recorded simultaneously (e.g., in UV plasma spectroscopy).

High Performance Integrated InAs Quantum Dot Laser Based Si Photonics Optical Transceiver
PI: Stefan Preble

The project is focused on the realization of high performance optical transceivers integrated onto a silicon chip using robust InAs quantum dot lasers. Specifically, this project will overcome one of the largest challenges in silicon photonics, which is the seamless integration of robust and low-powered lasers with other silicon photonics devices, where the lasers need to operate at relatively high ambient temperatures (70-80 'C) and the emission wavelengths need to be varied to achieve a multichannel laser array with large transmission bandwidth. Our approach is to bond III-V heterostructures that contain quantum dots onto silicon substrates. Quantum dots (QD) possess 3D confinement and delta-function like density-of-states (DOS), and as a result, and unlike their quantum well counterparts, have good temperature stability, low power consumption, high differential gain, and zero chirp and a-factor. In addition, they are spectrally broad due to large size distribution of the quantum dots, and as a result can be used to realize broadband laser sources. Furthermore, in order to realize high gain, and as a result low threshold power, we are uniquely aiming to directly integrate the lasers to waveguides through a butt-joint waveguide coupling scheme. This will enable all of the transceiver components to be integrated into the same plane, significantly increasing performance and decreasing the overall footprint ' in turn, allowing denser integration for overall higher bandwidth at lower powers.

Measuring the Pixel Response Function of Kepler CCDs to Improve the Kepler Database
PI: Zoran Ninkov
February 2016 - February 2019

Stellar images taken with telescopes and detectors in space are usually undersampled, and to correct for this, an accurate pixel response function is required. The standard approach for HST and Kepler has been to measure the telescope PSF combined ("convolved") with the actual pixel response function, super-sampled by taking into account dithered or offset observed images of many stars. This combined response function has been called the "PRF". However, using such results has not allowed astrometry from Kepler to reach its full potential. Given the precision of Kepler photometry, it should be feasible to use a pre-determined detector pixel response function (PRF) and an optical point spread function (PSF) as separable quantities to more accurately correct photometry and astrometry for undersampling. Wavelength (i.e. stellar color) and instrumental temperature should be affecting each of these differently.

Discussion of the PRF in the "Kepler Instrument Handbook" is limited to an ad-hoc extension of earlier measurements on a quite different CCD. It is known that the Kepler PSF typically has a sharp spike in the middle, and the main bulk of the PSF is still small enough to be undersampled, so that any substructure in the pixel may interact significantly with the optical PSF.

Both the PSF and PRF are probably asymmetric. The Center for Detectors is measuring the PRF for an example of the CCD sensors used on Kepler at sufficient sampling resolution to allow significant improvement of Kepler photometry and astrometry, in particular allowing PSF fitting techniques to be used on the data archive.

Quantum Silicon Photonics Measurement System
PI: Stefan Preble
September 2016 - September 2017

The primary objective of this Defense University Research Instrumentation Program (DURIP) project is to demonstrate quantum photonic circuits on a silicon chip by using a quantum photonic measurement system with ultra-low noise and high efficiency. Quantum information science has shown that quantum effects can dramatically improve the performance of communication, computational and measurement systems. However, complex quantum systems have remained elusive due to the large number of resources (photon sources, circuits and detectors) that need to be tightly integrated. Dr. Stefan Preble is realizing breakthroughs by integrating quantum circuits on a silicon chip and developing scalable building blocks based on ring resonators, which dramatically reduce the footprint of the circuits and enable novel functionalities. The quantum measurement system, consisting of a low-noise tunable laser and high efficiency single photon detectors, is a critical enabler of these Quantum Silicon Photonic chips.

Integrated Photonics Education at RIT
PI: Stefan Preble
January 2016 - June 2017

The objective of this project is to support AIM Academy (the education arm of AIM Photonics) by providing education modules for integrated photonics design, manufacturing, packaging and testing. We are also working to educate students, workforce, veterans and the community with: short courses, degree courses, establish an integrated photonics practice facility, assess workforce needs and develop an ME degree in Integrated Photonics Manufacturing in collaboration with MIT.

A Cryogenic Optical Camera for Attitude Control of Low-Temperature Sub-Orbital Payloads
PI: Michael Zemocov
May 2016 - May 2019

Charge coupled detectors (CCDs) are inoperable below 120K due to electron freeze-out effects and therefore, problematic in cryogenic applications. An alternative optical sensing technology, the scientific complementary metal-oxide-semiconductor (sCMOS) detector, offers the possibility of mega-pixel science-grade optical cameras operable to - IOK. The promise of a fully cryogenic optical detector is a compelling technology for NASA because it does not require active heating in the space environment. Such a detector enables instruments ranging from actively-cooled star trackers for sounding rockets to low-temperature deep space cameras. As a first step, The Center for Detectors is developing and flying an attitude-sensing camera employing a low noise, high quantum efficiency cryogenic sCMOS detector on a Black Brant IX sub-orbital vehicle. Images from the T=77K 5.5 mega-pixel sensor is processed by on-board software and pointing information is used to dynamically control the attitude of the payload with gyroscopes. The instrument design, fabrication, flight operations and data analysis is being performed by a diverse, multi-disciplinary team of undergraduate students to provide hands-on experience on a flight project under the leadership of a graduate student mentor and an experienced PI. The students are responsible for mechanical, optical, and electronic engineering activities; firmware and algorithm development; flight planning and operations; and project management, documentation control, and reporting. Following a successful initial flight, this system will fly on a NASA astrophysics payload to measure extragalactic light from the cosmic infrared background.

A Data Analysis Pipeline Simulator for a Millimeter-Wavelength Imaging Spectrometer
PI: Michael Zemocov
May 2016 - August 2017

The Center for Detectors is conducting a design study for software and data analysis for the Tomographic Ionized-carbon Mapping Experiment (TIME-Pilot) instrument, which is designed to make pioneering measurements of the redshifted 157.7 'm line of singly ionized carbon [CIIJ from the Epoch of Reionization (EoR). The EoR is the period in the Universe's history during which the first stars and galaxies formed, and whose intense ultra-violet (UV) radiation fields ionized the intergalactic medium. The New Worlds, New Horizons 2010 Astrophysics Decadal Report recognized the EoR as one of five scientific discovery areas where "new technologies, observing strategies, theories, and computations open . . . opportunities for transformational comprehension". This investigation is breaking ground for future investment from government and private funding agencies by improving our understanding of the instrument design and expected performance.

Air Force STTR Phase 1 AF16-AT01: "Wafer-Level Electronic-Photonic Co-Packaging"
PI: Stefan Preble
November 2016 - August 2017

This program is developing flexible, low-cost packaging techniques for largescale, integrated optoelectronic systems based on heterogeneously integrated photonic and electronic chips.

Ultracompact Graphene Optical Modulators
PI: Stefan Preble
June 2013 - May 2017

The objective of this research is to explore ultracompact graphene optical modulators for future on-chip optical communications. The approach is to systematically explore the unique electro-optic properties of graphene, and to greatly enhance the interaction of graphene with light based on novel waveguides and platforms. In particular, graphene in a waveguide can be tuned with anomalous optical properties with a suitable gate voltage, which is being employed to develop the modulators.

This project is systematically exploring novel graphene-sandwiched optical waveguides based on the unique properties of graphene. This research is one of the first experimental attempts to demonstrate optical modulators at nanoscale, and one of the first systematic explorations of graphene for all-optic modulation. The research results may revolutionize nanophotonic technology and on-chip optical interconnects, and contribute to the fundamental theory and techniques for newly developed Graphene Optoelectronics and Graphene and 2D Semiconductor Physics.

Graphene is a topic that is of great interest to the general public. The outreach activity, "From Graphite to Graphene", is helping STEM education by introducing K-12 students to the science and fabrication of nanotechnology for a wide range of applications. The students involved in this research are participating in nanotechnology development, and the results developed from the research activities will be incorporated into several college courses. Collaboration with external companies may commercialize valuable products for industrial and military applications. Under-represented students from Women in Engineering and North Star Program are involved in this project.

Single Photon Counting Detectors for NASA Astronomy Missions
PI: Don Figer
September 2013 - August 2015

Single photon counting detectors have the potential to be the next big advancement for NASA astronomy missions. The ability to count single photons facilitates science goals that are impossible even with current state-of-the-art detectors. Single photon counting detectors are the future, and many different implementations are in development. In the next 20 years, many NASA missions requiring single photon counting will be proposed, but which single photon counting detector implementations best suit the performance needs of NASA's astronomy programs? The goal of the proposed research is to characterize (theoretically and physically) three unique implementations of single photon counting detectors, benchmark their operation over a range of performance characteristics, and provide comprehensive justification for the superiority of one of the implementations for each of these NASA astronomy applications: exoplanet detection, high-contrast imaging, adaptive optics, and array-based LIDAR.

The research plan in this project includes simulation, characterization, and evaluation of the performance of three types of semiconductor photon counting detectors for use in NASA astronomy missions: Geiger-mode (GM) APDs, linear-mode (LM) APDs, and Electron Multiplying (EM) CCDs.

The main goal of this project is to provide the basis of comparisons for several types of fundamentally different single photon counting detectors by producing a table of comparisons and recommendations for various applications. All detectors must be sensitive to single photons, be scalable to large array formats, and have high QE (in the visible, UV, NIR, IR, and Far-IR wavelengths). This research is advancing preliminary work by adding new characterization methods and performance benchmarks, and by comparing the different devices at predetermined milestones during the project. The recommended detector(s) should function well at high readout frequencies without significant read noise (leading to improved temporal sampling), have very low noise for increased SNR at low fluence levels, and be implemented (or able to be in the near future) on large arrays. Even though single-photon counting detectors share a common performance benchmark (discerning individual quanta), differences between various implementations make some more efficient than others.

New Infrared Detectors for Astrophysics
PI: Don Figer
June 2012 - May 2017

Infrared arrays with HgCdTe as the light-sensitive layer, such as have been developed up to sizes 2048x2048 pixels for the James Webb Space Telescope, a re near-ideal detectors for imaging and spectroscopy in the region ~1-5 'm. However current construction requires fabrication on CdZnTe substrates, which are expensive and limited in availability. The key to making larger (up to 14,000x14,000 pixels) and less expensive infrared detectors lies in using silicon wafer substrates, since large silicon wafers are common in the high volume semiconductor industry and their coefficient of thermal expansion is well-matched to that of the silicon readout circuits.

While the use of silicon substrates has been a major goal in the field of developing infrared detectors, the main limitation over the past 15 years has been the large lattice spacing mismatch between silicon and commonly-used infrared light-sensitive materials. The mismatch causes defects that can result in higher dark current, or valence holes that lead to reduced quantum efficiency and image persistence.

Enlisting the expertise and fabrication capabilities of Raytheon Vision Systems, detector expert Dr. D. Figer of the Rochester Institute of Technology plans to deposit the HgCdTe light-sensitive layer on silicon using the very promising technique of Molecular Beam Epitaxy (MBE). By maintaining vacuum during MBE processing, defect density has been shown to be reduced and the resulting prototype devices have achieved the anticipated performance. Very large, affordable infrared arrays is essential for making optimum use of the proposed ~30m class ground-based telescopes and their availability has clear implications for fields beyond astronomy, including medical imaging and remote sensing.

A Zero Read Noise Detector for Thirty Meter Telescope (TMT)
PI: Don Figer

The key objective of this project is to develop a new type of imaging detector to enable the most sensitive possible observations with the world's largest telescopes, i.e. the TMT. The detector will effectively quadruple the collecting power of the TMT, compared to detectors currently envisioned in TMT instrument studies, for the lowest light level observations. It would have fundamental importance in ground-based and space-based astrophysics, Earth and planetary remote sensing, exo-planet identification, consumer imaging applications, and homeland safety, among many others. Measurable outcomes include being able to see further back into the infancy of the Universe to taking a better picture (less grainy) of a smiling child blowing out the candles at her birthday party. The detector will be quantum-limited (zero read noise), be resilient against the harsh effects of radiation in space, consume low power, operate over an extremely high dynamic range, and be able to operate with exposure times over one million times faster than typical digital cameras. The RIDL is teaming with MIT/Lincoln Laboratory to leverage their Geiger-mode Avalanche Photodiode technology for developing the imaging detector. The project is funded through the Gordon and Betty Moore Foundation.

A Photon Counting Detector for Exoplanet Missions
PI: Don Figer
February 2016 - February 2017

The objective of this project is to advance photon-counting detectors for NASA exoplanet missions. A photon counting detector can provide zero read noise, ultra-high dynamic range, and ideal linearity over the relevant flux range of interest. It could be the best realizable detector for a planet finding spectrograph, and it would have outstanding properties as a wavefront sensor or detector in the imaging focal plane. The benefit of this device is that it dramatically improves the sensitivity beyond what is capable with non-photon counting detectors, thereby increasing science return for a fixed mission life; for low-light-level cases, such as spectroscopy, the device can reduce the necessary exposure time for detecting planetary features by 50-80%. The device always operates in photon counting mode and is thus not susceptible to excess noise factor that afflicts other technologies. It continues operating with shot-noise limited performance up to extremely high flux levels. Its performance is expected to be maintained at a high level throughout mission lifetime in the presence of the expected radiation dose.

LIDAR Imaging Detector
PI: Don Figer
August 2008 - July 2012

In collaboration with MIT/Lincoln Laboratory, the RIDL is developing an imaging Light Detection and Ranging (LIDAR) detector for NASA planetary space misisons. The device will have a pixelated array of independent Geiger-mode Avalanche Photodiodes that can asynchronously measure laser light time of flight. The output will be three-dimensional images providing distance measurements for each pixel. The device will have a timing accuracy of ~100 picoseconds, thus enabling a ranging accuracy ~1 cm, or roughly two orders of magnitude better than existing LIDAR instruments.

The nature of GLIMPSE 81: a star cluster to rival Westerlund 1
PI: Don Figer
June 2010 - June 2014

This project uses Chandra/ACIS observations of a young star cluster. The X-ray emission from this cluster, already observed in previous low-resolution observations, will be resolved by Chandra into many components. Analysis will include separation of the diffuse X-ray emission from the point-sources, and a spectral analysis of each source. The data from this project will be combined with those from other observations in order to perform a multiwavelength analysis.

Clumping in OB-star winds
PI: Don Figer
December 2012 - June 2015

Massive stars, their nature and evolution, play a important role at all stages of the Universe. Through their radiatively driven winds they influence on the dynamics and energetics of the interstellar medium. The winds of OB stars are the most studied case. Commonly, the mass-loss rates of luminous OB stars are inferred from several types of measurements, the strengths of UV P Cygni lines, H-alpha emission and radio and FIR continuum emission. Recent evidence indicates that currently accepted mass-loss rates may need to be revised downwards when small-scale density inhomogeneities (clumping) are taken into account. This project uses Herschel Space Telescope data to consistently treat ALL possible diagnostics, scanning different parts of the winds, and analyzed by means of 'state of the art' model atmospheres, will permit the determination of true mass-loss rates.

Guide Detector Evaluation for the Large Synoptic Survey Telescope (LSST)
PI: Don Figer

The RIDL is testing prototype optical guide detectors for LSST. We have developed a guider testbed that simulates the expected image motion that the LSST focal plane will experience. The testbed will be used to validate guide detector performance against LSST requirements.

Sigma-Delta Detector
PI: Don Figer

In collaboration with the University of Rochester, the RIDL is developing very low noise CMOS imaging detectors for NASA space astrophysics and planetary missions. These devices promise sub-electron read noise in a direct-readout architecture that is resilient against the transient and long-term effects of radiation. The novel readout circuit uses a one-bit sigma-delta oversampling comparator design developed by Zeljko Ignjatovic and Mark Bocko (University of Rochester). The light-sensitive silicon wafer is being designed and fabricated by RIDL and the RIT Semiconductor & Microsystems Fabrication Laboratory. NASA/JPL will delta-dope the backside of the detector for enhanced ultraviolet sensitivity. The wafer and the readout will be bump bonded together to produce a hybrid detector with good sensitivity from the ultraviolet through near-optical infrared.

A NICMOS survey of newly-identified young massive clusters
PI: Don Figer
January 2009 - December 2012

We are on the cusp of a revolution in massive star research triggered by 2MASS and Spitzer/GLIMPSE, and now is the ideal time to capitalize on these projects by performing the first survey of massive stars in young stellar clusters throughout the Galactic plane. A search of the 2MASS and GLIMPSE surveys has produced over 450 newly-identified massive stellar cluster candidates in the Galactic plane which are hidden from our view at optical wavelengths due to extinction. In this project, we are using 29 HST orbits to image the most promising candidate clusters in broad and narrow band filters using NICMOS. The observations will be complemented with approved Spitzer and Chandra programs, numerous approved and planned groundbased spectroscopic observations, and state-of-the-art modelling. We expect to substantially increase the numbers of massive stars known in the Galaxy, including main sequence OB stars and post-main sequence stars in the Red Supergiant, Luminous Blue Variable and Wolf-Rayet stages. Ultimately, this program will address many of the fundamental topics in astrophysics: the slope to the initial mass function (IMF), an upper limit to the masses of stars, the formation and evolution of the most massive stars, gamma-ray burst (GRB) progenitors, the chemical enrichment of the interstellar medium, and nature of the first stars in the Universe.

Mid-Infrared Spectroscopy of the Most Massive Stars
PI: Don Figer

The most massive star that can form is presently defined by observations of a class of very rare stars having inferred initial masses of ~200 solar masses. There are only a few such stars in the Galaxy, including the Pistol Star, FMM362, and LBV 1806-20, the first two being located near the Galactic center, and third located in the disk near W31. Each has only recently been identified as so massive within the past 10 years through the analysis of infrared observations, but they are otherwise too faint, due to extinction, to observe at shorter wavelengths. These stars appear to be very luminous (L>10^6.3 solar luminosities), "blue" (T>10000 K), and variable (delta K~1 mag.), and the Pistol Star has ejected 10 solar masses of material in the past 10000 years. In addition, these stars have near-infrared spectra similar to those of prototypical Luminous Blue Variables, i.e. Eta Car and AG Car. Given their apparent violation of the Humphries-Davidson limit, they are presumably in a short-lived phase of stellar evolution that is often associated with rapid mass-loss through episodic eruptions of their outer atmospheres. We propose to determine the physical properties of these stars and the velocity and ionization structure in their winds by using spectra obtained with the high resolution modes of the Infrared Spectrograph (IRS) on the Spitzer Space Telescope. The 10 to 40 'm wavelength region is ideally suited for accessing a variety of lines from transitions of hydrogen, helium, iron, silicon, sulfur, among others; indeed, through our models, we predict that sufficiently sensitive spectra will yield over 300 spectral lines. In addition, we predict that the mid-infrared continuum will be dominated by free-free emission generated in the thick winds associated with these stars, an effect that should be clearly detectable in the spectra.

Sandia FPGA Imaging Acquisition Software Development
PI: Don Figer
June 2008 - September 2010

RIDL developed HDL (Hardware Description Language) software for a FPGA (Field Programmable Gate Array) evaluation board for Sandia National Laboratories. The HDL software programs the FPGA chip to transfer digital video rate image data from the evaluation board to a windows based PC using the Camera Link data transfer format. Once the Camera Link data format became available, data acquisition software for the PC was developed to capture and display the imagery on the PC.

The Pre-Supernova Mass-Loss Behavior of Red Supergiants
PI: Don Figer

The mass lost by massive stars as they pass through the Red Supergiant (RSG) phase is a crucial determinant in the terminal mass of the star, the nature of the resulting supernova explosion and the stellar end-state. However, up until now studies of this quantity have been problematic, owing to the low numbers of known RSGs and the difficulty of observing in the mid-IR. Here, we capitalize on the recent discoveries of two remarkable Galactic clusters containing unprecedented numbers of RSGs, and use the capabilities of Spitzer to undertake a comprehensive and unique study of the pre-SN mass-loss of massive stars. We will use Spitzer/IRS observations in conjunction with state-of-the-art dust models to provide the first quantitative investigation of the mass and composition of the pre-SN ejecta as a function of age and metallicity. This study is vital in determining the mass-loss behaviour of RSGs in particular, and the nature of supernova progenitors in general.

A Very Low Noise CMOS Detector Design for NASA
PI: Don Figer
February 2007 - May 2011

The purpose of this project is to design, fabricate, and test a novel new detector having many advantages over present CCD and CMOS devices. The hybrid CMOS detector is expected to have low noise, radiation tolerance, low power dissipation, low mass and robust electronics. Its low noise is derived from a novel on-die digitization circuit based on a sigma-delta feedback loop.

The Most Massive Stars
PI: Don Figer
February 2006 - February 2010

Until the Spitzer Space Telescope, there was no wide area survey that could identify massive stars at all distances in the Galaxy. Indeed, the sample of known O-stars is woefully incomplete, as it has largely been generated using optical observations that suffer from the absorption produced by dust in the disk. We will find and measure the physical properties of the most massive stars in the Galaxy using HST, Spitzer, Chandra, SOFIA, and ground-based observatories, using a survey technique that probes the majority of the Galaxy. This program addresses fundamental questions whose answers are basic requirements for studying many of the most important topics in Astrophysics: the formation and evolution of the most massive stars, the effects of massive stars on lower mass protostellar/protoplanetary systems, gamma-ray burst progenitors, nature of the first stars in the Universe, chemical enrichment of the interstellar medium, Galactic gas dynamics, star formation in starbursts and merging galaxies (particularly in the early Universe). The results of our program will influence the science programs for future NASA projects, i.e. JWST, SOFIA, SIM, TPF-C, and TPC-I.