Chee Wei Wong - US grants

The objective of this Sensors and Sensor Networks (NSF 05-526), Sensors Interdisciplinary Research Group (SIRG) project is to conduct fundamental investigations towards the implementation of novel subwavelength microphotonic sensors for applications in manufacturing environments by studying the fundamental limits in the spatial and temporal resolutions of these sensors, developing innovative embedding techniques, and testing sensors in real manufacturing processes. Specifically, the research group will study the fundamental limit in the spatial and temporal resolution of integrated microphotonic sensors for temperature and strain measurements. Microphotonic sensors will be embedded into metals to ensure sensor survivability and reliability in manufacturing environments. An innovative batch fabrication of metal embedded subwavelength microphotonic sensors will be developed. Techniques will be studied and optimized for transferring metal embedded microphotonic sensors into larger metallic structures in manufacturing environments. The research group also seeks to implement these sensors in real manufacturing testbeds and utilize sensing data to achieve a better fundamental understanding of two important processes, chemical mechanical planarization for semiconductor manufacturing and continuous casting for steel production.

If successful, this research will significantly advance sensor technologies through an interdisciplinary study of subwavelength photonic sensors, sensor embedding into metals, and sensing in real manufacturing processes. Novel sub-wavelength microphotonic sensors along with innovative embedding techniques will yield measurements with high spatial resolution, high sensitivity, and fast temporal response. The success of this project can significantly advance fundamental knowledge for chemical mechanical planarization and continuous casting of steel processes. The successful implementation of microphotonic sensor arrays could advance the fundamental understanding of numerous other manufacturing processes, thus significantly improving productivity and generating significant cost savings. Industrial testbeds will facilitate immediate technology transfer to industry, in addition to planned publications, short courses to industry, and patents. Undergraduate and graduate students will be able to get hands-on experience in subwavelength microphotonic technology. Summer workshops will be held and suitable science modules will be developed for K12 students and teachers. The PIs will also attract, retain, and engage students from under-represented groups.

The objective of this research is to investigate active nanoscale optical interconnects,
based on nonlinear photonic crystal nanocavity switches. Active optical interconnects
form the basis of a reconfigurable flow of information on CMOS microelectronic chips,
with ultralow latency, ultrahigh bandwidth, low power dissipation, and high-density
integration feasibilities. The approach is based on silicon nanocavities for immediate
CMOS compatibility, with insertion of nonlinear nanomaterials or nanopatterned
materials to achieve ultralow switching thresholds and high-speed operations. The cavity
designs will take advantage of photonic crystal nanolattices for strong field enhancements
and material interactions. All-optical switching through Kerr nonlinearities will also be
explored. Theoretical designs and concepts will be investigated via full three-dimensional
finite-difference time-domain simulations, and devices will be fabricated and
characterized at Columbia.
In terms of broader impact, this exploratory program addresses several of the core issues
for continued CMOS VLSI scaling. It is thus of general interest for engineers and
scientists active in optical data communication and silicon microelectronics. The program,
in addition, will support the interdisciplinary training of students in nanophotonics for
these industries. Moreover, the program will participate in the Columbia Undergraduate
Research Opportunities Program (UROP) and will partner with the NSF/Columbia NSEC
Nanoelectronics and MRSEC Nanomaterial programs with the support of one summer
undergraduate research experience. A university-wide seminar series on Nanophotonics
will be developed for the Fall 2005 semester, targeted at first-year graduate students and
undergraduate seniors, and a series of follow-on activities involving local K-12 students
will be developed.

Intellectual Merit

The scaling of switching elements to nanometer lengthscales raises a formidable challenge to the internal processing of the optical data packets while maintaining a memory-free switching fabric. At the device level,nanophotonic logic elements for information processing will follow two parallel paths:electro-optic switch nodes employing high-index-contrast nanophotonics and an all-optical switch node based on photonic band gap nanostructures.Both implementations will demonstrate the feasibility for ultra-dense nanophotonic integration,towards the ultimate realization of an ultra-low latency computational network on the semiconductor chip.

Broader Impact
Specific outreach modules on optical networks and nanophotonics will be developed for K-12 school teachers,and presented at schools with a high proportion of minority and underrepresented students around the New York metropolitan area.Undergraduates from our summer research programs will be actively recruited to graduate studies at Columbia and Georgia Tech.
The proposed program aims to harness the extraordinary capabilities of nanoscale photonics and the
immense communication capacities of optical networks to create a high-risk,revolutionary paradigm in
high-performance computation.Our approach tackles what is perhaps the most critical performance
challenge to future large-scale computing systems,namely the mounting communications bottleneck.

The uniquely integrated program merges expertise in fundamental nanophotonic physics, optical systems,
network topology,and performance analysis,and thus presents an unparalleled opportunity for truly
revolutionary advances in high-performance computing.Beyond the direct impact on future high-end
computing systems,this proposed work may potentially introduce highly innovative photonic
technologies towards new commercial applications.By demonstrating the viability of optical packet
switching and nanophotonic subsystems businesses which currently deploy high-capacity fully electronic
switches may consider the future insertion of nanophotonic-based interconnection networks.

ENHANCED RAMAN PHENOMENA IN PHOTONIC CRYSTAL NANOSTRUCTURES: SCIENCE AND APPLICATIONS

0622069
Wong, Chee Wei, Columbia University

Intellectual Merit: Recent years have witnessed remarkable developments on Raman sources and amplifiers in silica optical microstructures and silicon waveguides. Based on either ultra-high quality factors (Q) found in silica microspheres for long photon-matter interaction times or tight wavelength-scale confinement in silicon waveguides, these efforts point to the feasibility of achieving on-chip optical signal gain and lasing at tunable wavelengths in silicon. The PI proposes to address these possibilities and further the advancements by investigating the significantly enhanced Raman phenomena in silicon-based photonic crystal nanostructures. Photonic crystals offer the unique ability to achieve high Q/Vm nanocavities (where Vm is the modal volume), and the arbitrary control of the dispersion characteristics to increase the photon-matter interaction times. The PI will study various low-loss photonic crystal cavities, consisting of one-dimensional and two-dimensional, single and coupled, as well as interaction with waveguides for high-density photonic integrated circuits, for enhancement of stimulated Raman scattering. The PI's theoretical developments will be complemented with experimental efforts and results in both device nanofabrication and physical measurements. This investigation presents a route to silicon-based optical amplification and wavelength-selectable lasing for electronic-photonic integrated circuits, and supports the study of cavity-enhanced nonlinear optics in subwavelength nanostructures.

Broader Impact: This program investigates the important goal of low-threshold wavelength-selectable silicon lasing through Raman scattering in photonic crystals. This program will support the training and education of students at the graduate, undergraduate and high-school levels. Specific outreach modules on nanotechnology and nanophotonics will be developed for K-12 school teachers and presented at schools with a high proportion of minority and underrepresented students around the New York metropolitan area. The PI will participate actively in existing outreach programs as well as provide an enriching laboratory environment for the training and education of graduate, undergraduate, and high-school students.

0701729
Daniel Attinger, Columbia University
Optofluidics for Next Generation of Laboratory-On-A-Chip


Intellectual Merit: The proposed research will integrate versatile and ultrafast optical sensors with extremely efficient fluid handling techniques into microfluidic chips. These optofluidics chips will perform tasks essential to chemistry and biology, such as mixing, purification, and protein adsorption. These tasks will be executed and monitored at unprecedented frequencies, close to MHz rates. The innovations of the project will be to develop universal integrated sensors with a footprint of a few micrometers, based on state-of-the-art high quality factor optical nanostructured resonators, and to develop fast fluidic mixing based on novel interfacial and segmented flow techniques.

Broader Impact: Remarkable advances in the miniaturization and integration of fluid handling have allowed large-scale integration of thousands of microchannels and valves in so-called microfluidic chips for novel chemical and biological applications, such as particle synthesis and genomic analysis. In current microfluidic chips, the operation frequencies are limited by diffusion-based mixing; also, sensing methods are slow and bulky, many requiring a microscope and visualization setup. The proposed optofluidics chips, integrating high-resolution optical sensors with fast microfluidic capabilities, are expected to contribute significantly to increase the processing power of microfluidic chips, in a similar way that integrated transistors have improved the processing power of microelectronic chips. The educational components of this interdisciplinary research involve theory and numerical design, device micro- and nano-fabrication, as well as fluidic and optical experiments. This program will support two graduate students and summer Research Experience for Undergraduates (REU) activities. It involves cross-boundary topics in Applied Physics, Mechanical, Electrical and Biomedical Engineering. Specific education modules on optofluidics, microfluidics and optical sensors will be developed for K-12 school teachers and presented through two summer workshops for minorities and underrepresented students around the New York metropolitan area, in the Bronx and Harlem.

ECCS 0725707
Keren Bergman, Columbia University

Highly scalable and energy efficient interconnection networks are critical to the future performance of advanced computing systems. Photonic interconnection networks offer a potentially disruptive technology solution that can provide ultra-high throughput, minimal access latencies, and low power dissipation that remains independent of capacity.

Intellectual Merit: In this proposed program we aim to address the design and implementation of optical systems in broadband networks by coupling advancements in silicon nanophotonics with the tremendous capacity of optical data communications. The merging of these two fields offers an unparalleled opportunity in creating a new paradigm of truly optical domain integrated systems based on dynamic nanophotonic building blocks. In this proposed research program, core nanostructured photonic components ? consisting of fast and power efficient switch nodes and delay lines ? are realized to enable an integrated optical network for ultrahigh capacity data routing. The novel network architecture is specifically designed for nanoscale integration and implementation of truly end-to-end transparent lightwave paths for high capacity data communications.

Broader Impact and Outreach: The proposed program tackles what is perhaps the most critical performance challenge to the future scaling of performance computing systems, namely the mounting communications infrastructure bottleneck. The insertion of a photonic interconnection network can fundamentally alter the performance and energy efficiency roadmap for future generations of computing systems. In terms of education, this interdisciplinary combination of networks and optical devices aspects will be introduced into revised and new undergraduate and graduate course sequences that emphasize and explore their physical- and logical-layer inter-dependences. The proposed program further offers a unique opportunity to train graduate students in a vertically integrated team-oriented research, with specific outreach on networks and optics to K-12 schools with high proportion of underrepresented minorities around the New York metropolitan area.

Proposal Number: ECCS-0747787

Proposal Title: CAREER: Nonlinear and nonclassical optics in ultrahigh-Q/V mesoscopic cavities: Science, Education and Applications

PI Name: Wong, Chee Wei

PI Institution: Columbia University

CAREER: Nonlinear and nonclassical optics in ultrahigh-Q/V mesoscopic cavities: Science, Education and Applications

The objective of this research is to examine light-matter interactions at the mesoscopic scale in synthetic optical nanostructures. The approach is: (1) further demonstrate state-of-the-art photonic crystal cavities with ultrahigh-Q/V ratios, (2) examine nonlinear nanophotonics based on these strongly localized optical cavities with long photon lifetimes, and (3) examine the coherent atom-field interactions available with our nanocavity-quantum dot system.

Intellectual Merit: Recent successes in device nanofabrication enable the control of light-matter interactions from first principles. The PI will examine the localization of light in wavelength-scale optical nanocavities with long photon lifetimes, limited only by intrinsic material absorption. Coupled cavities will be examined, enabled by a proposed digital tuning approach for matching chip-scale resonance and transitions with nanoscale emitters. Second, the PI will examine ultralow threshold nonlinearities in these nanocavities for frequency conversion and optical logic elements. Third, the PI examines an approach towards quantum dot ? nanocavity interactions in the silicon CMOS infrastructure and in the near-infrared, with coupled coherent interactions.
Broader Impact: These studies on nonlinear and nonclassical optics afforded by the ultrahigh-Q/V optical cavities present an approach to examine and fundamentally control light-matter interactions at the nanoscale, as well as a confluence of solid-state physics and optical nanosciences. The interdisciplinary science and engineering training and education will also involve working with minority, women and high-school students in under-represented communities. The PI participates in a technology outreach program, and will further improve the graduate and undergraduate curriculum.

The objective of this program is to examine the ultrafast nonlinear interactions in slow-light photonic crystals, based on recent advancements and towards chip-scale optical signal processing. Experimental observation, along with device nanofabrication, theory and numerical modeling, will be examined in this program.

The intellectual merit is composed of three interrelated Research Thrusts. In Thrust I temporal solitons and ultrafast pulses will be examined in slow-light photonic crystals, in addition to the characterization of the ultrafast pulses. In Thrust II, the program will extend the single electromagnetic wave nonlinear - dispersive interactions to the nonlinear coupling between two electromagnetic waves. In Thrust III, the program will examine four-wave mixing, including optical signal processing.

The broader impacts are the enhanced ultrafast nonlinearities in slow-light photonic crystals for ultrashort pulse generation and frequency conversion, in next-generation chip-scale optical signal processing and communication modules. The Educational outreach and programs will benefit minority and underrepresented groups, K-12 students, high-school teachers, graduate and undergraduate students. The educational tasks involve the outreach to under-served education programs in Harlem and Lower Bronx by working with the GK12 programs and the Double Discovery Center summer program, to develop optical nanoscience and technology teaching modules. The program will also work with the high-school science and physics teachers in Harlem to develop an elective teaching module, involving both theoretical and experimental components, and a ?hands-on? module, to reinforce the advances at intersection of optical physics with nanoscience and technology.

The goal of this NUE in Engineering program entitled, "NUE: Transforming Nanoscale Science and Engineering Undergraduate Education", at Columbia University, under the direction of Dr. Chee Wei Wong, is to create an institutionalized cross-disciplinary nanotechnology undergraduate program, reaching across multiple departments to serve a targeted ~90 (25% of cohort) undergraduates. Seven laboratory modules on nanoscale science and engineering will be developed, based on scientific advances by the project team such as in graphene, nanomechanics, nanostructured solar photovoltaics, and nanoelectronics. These hands-on modules
will be taught in conjunction with a theoretical numerical simulations class on the foundations of nanotechnology.

The classes will reach out across Columbia University and Barnard College (an undergraduate women's college), and the laboratory modules can further serve as stand-alone experiments in other nanoscale related curricula. In addition, research experiences for undergraduates will be provided under this program, as well as summer internships at GE Global Research and the Center for Functional Nanomaterials at Brookhaven National Laboratory. All course materials will be made freely available online for broad dissemination. Lectures in the theoretical foundations class will be recorded and made available for asynchronous download.

The strongly quantum-confined III-nitride material system fundamentally offers the distinct opportunity to operate at high temperatures (200K or more) for scalable semiconductor cavity quantum electrodynamics. Supported by advances in materials growth, optical spectroscopy, and first-principles modeling, this research examines the combination of InGaN quantum dots with mesoscopic optical cavities for solid-state cavity quantum electrodynamics. Optimization of the materials growth and device nanofabrication is performed, to examine low defect density growth. Single quantum dots are targeted for light emission and its modification, as well as nonclassical optics. This research combines the expertise of two groups: III-nitrides materials growth at the Institute of Materials Research and Engineering (IMRE) in Singapore, and optical characterization and photonic crystals at Columbia University. The devices will be optically probed for the exciton characteristics. Microcavities such as whispering gallery modes and photonic band gap cavities will be examined.

This Materials World Network project enables critical complementary efforts between scientists in the United States and Singapore, providing invaluable experience to the graduate students and senior scientists in different working environments. This collaboration also seeds future efforts in the area of solid-state physics and quantum information processing. This research is complemented with international education and exchange efforts, involving iterated feedback and interactions between the two institutions on materials growth and optical spectroscopy, co-supervision of PhD students, participation of the US personnel internationally, and exchange of senior research staff. Furthermore, high-school teacher and undergraduate student exchanges are supported. To support this international activity, video teleconference reviews are also held. The research developed in this collaborative program will be disseminated on the web as well as through international conferences and publications.

This Integrative Graduate Education and Research Traineeship (IGERT) award facilitates the unique interdisciplinary training of Ph.D. scientists and engineers in the field of sustainable and renewable energy solutions. The energy economy is an immediate and grand challenge that must be tackled by current and future generations of scientists and engineers.

Intellectual Merit: This program addresses this challenge by focusing on technology innovations in two subsystems of direct relevance: next-generation solar photovoltaics, and next-generation efficient optical data and communications networks. Both subsystems involve the manipulation of photons, through the realization of physical nanostructured devices and new spectroscopically-characterized functional materials, to deliver energy efficiencies dramatically better than current levels. The cross-training scientific research is synergistically integrated with innovative educational approaches and an emphasis on underrepresented groups.

Broader Impacts: This program addresses two main aspects of the energy challenge - efficient cost-competitive solar photovoltaics and energy-efficient optical networks - through cross-disciplinary advances in materials, devices and modular subsystems. This IGERT trains the next-generation of scientists and engineers to become leaders in shaping our country's renewable energy economy and policy. Effective implementation of solar photovoltaics requires appreciation of the societal context as well as a global awareness. Additionally, effective implementations of high-performance communication networks have security implications beyond traditional boundaries. The international partner sites are critical and integral to the training, providing materials growth through molecular-beam-epitaxy, real-world data network applications, and third-world photovoltaic deployment. Working with major industrial partners, the IGERT will conduct outreach to undergraduate and K-12 schools in Harlem and Nashville, encouraging underrepresented groups to enter science, technology, engineering, and mathematics areas of higher education.

IGERT is an NSF-wide program intended to meet the challenges of educating U.S. Ph.D. scientists and engineers with the interdisciplinary background, deep knowledge in a chosen discipline, and the technical, professional, and personal skills needed for the career demands of the future. The program is intended to catalyze a cultural change in graduate education by establishing innovative new models for graduate education and training in a fertile environment for collaborative research that transcends traditional disciplinary boundaries.

The objective of this program is to examine the integration of optical and fluidic networks into microchips, to sense and manipulate complex fluids for life science applications. The program will examine silicon-based label-free optofluidic chips with enhanced sensing resolution and manipulation capabilities.

The intellectual merit is to create a transformative science base for wavelength-scale integrated optofluidics based on optical resonators, with collaborative efforts with GE Global Research Center. This technology can perform high spatial resolution sensing, while seeking to significantly improve the refractive index measurement sensitivity. Approaches will be pursued for reduced noise and increased specificity. The second thread of this work will advance concepts such as optofluidic multiplexers and demultiplexers in the toolbox of microfluidic chips. Optical waveguide arrays with switchable laser excitation will be examined. A fundamental advantage of our technology over conventional free-space optical trapping is that the resolution can be sub-diffraction with the subwavelength photonic devices.

The broader impacts are the development of high-sensitivity universal integrated optical sensors that will enhance Lab-on-a-Chip functionalities. The proposed silicon-based optofluidic integration is scalable to large arrays for high throughput analysis, and can be manufactured within the vast silicon infrastructure. The proposed optofluidic chips can significantly increase the processing power of microfluidic chips, for industrial applications such as label-free biomolecule sensing, manipulation, and active control. The educational components of this interdisciplinary research include joint PhD student advising, undergraduate internships at GE, outreach to high-school teachers, and a joint annual industrial-university colloquium.

The research team is developing a photonic crystal platform technology based on negative refraction superlattices designed to implement high-performance phase modulators and tunable birefringent filters for use in optical communication modules. This technology is with chip-scale photonic crystal elements, highly wavelength-dispersive and potentially low-loss structures allows for high-density integration into modules. Since the devices are based on negative refraction photonic crystal superlattices which have strong wavelengths and phase sensitivity, they have low-voltage/power requirements for modulation.

Current optoelectric modules are large and require high power and high voltages. This technology provides a small, low power, low voltage module. The smaller size, would enable devices to be integrated into large numbers on silicon chips and enhance communications technologies.

Principal Investigator: Chee Wei Wong
Number: 1438147

The sun represents the most abundant potential source of pollution-free energy on earth. Solar cells for producing electricity require materials that absorb the sun's energy and convert its photons to electrons, a process called photovoltaics. To be competitive with fossil fuels, the cost of solar photovoltaic (PV) systems must be reduced, which is realized in part by increasing the solar energy conversion efficiency and by reducing the cost of solar PV materials. Recently, new photovoltaic materials have been discovered that harness the quantum physics behavior of inorganic semiconductor compounds ordered at the nanoscale to increase the solar energy conversion efficiency. The discovery of new and inexpensive materials for this next generation of photovoltaic devices is enabled by fundamental understanding of the interaction of light with these materials. The goal of this project is to develop a fundamental understanding of quantum physics processes in nanostructured photovoltaic materials which convert a single photon from light into multiple electrons, and thus surpass the single electron Shockley Queisser limit. The research will make use of advanced spectroscopic techniques which can probe multiexciton generation processes at ultrafast scales. Educational activities offered by the project focus on the development of a series of teaching and laboratory modules on solar energy, nanoscience, and sustainable energy, with content targeted separately to grade-school level students, low income, college-bound high school students in the New York City area, and undergraduate students at Columbia University.

Technical Description

The overall goal of this project is to develop a fundamental understanding of multi-exciton generation in nanostructured photovoltaic materials. The proposed research will study ultrafast multiexciton kinetics and generation in zero-dimensional and surface-modified nanostructures, as well as ultrafast multiexciton kinetics and collection in one-dimensional nanostructures and assemblies. This information will be used to harness multiexciton energy and electron transfer processes in nanostructured photovoltaics for improved solar energy conversion efficiency. Super-continuum ultrafast spectroscopy will be used to probe multiexciton kinetics and multiexciton efficiencies in semiconducting nanocrystals, nanorods, and nanostructures to elucidate the fundamental mechanisms. These studies will be extended to examine exciton and electron transfer of nanostructures in transparent high-mobility graphene electrode photovoltaics, using time- and spectrally-resolved studies and fast exciton quenching through blinking statistics of single nanostructures. Educational and outreach activities offered by the project focus on the development and delivery of a series of teaching and laboratory modules on solar energy, nanoscience, and sustainable energy, with content targeted separately to grade-school level students, low income, college-bound high school students in the New York City area, and undergraduate students at Columbia University.

Recent advances in nanofabrication and precision measurements in cavity optomechanics have afforded remarkable new boundaries in quantum mechanical ground state preparation, optomechanical radio frequency clocks and oscillators, and precision sensing of motion and forces. Motion acceleration sensing is a critical platform for seismic geophones monitoring with applications in structural health monitoring, borehole and seismic underground imaging, inertia navigation, as well as sensors in consumer electronics. Through optical driving and readout, recent efforts in optomechanics have demonstrated remarkable nanomechanical motion and force detection at and below the standard quantum limits, supporting potential breakthroughs in sensing platforms. This award supports next-generation chip-scale accelerometers through optomechanical readout with unprecedented sensitivities, at 100× to 1000× better sensitivities than state-of-the-art commercial accelerometers. This provides new platforms in structural health monitoring, borehole and seismic underground imaging, and inertia navigation. This program outreaches to targeted underrepresented communities, delivering teaching modules to K-12 students and the high-school science curriculum, while developing a new hands-on laboratory course on mesoscale sensing and sensors to train the undergraduates and graduates on next-generation motional and force detection.

In this award we will examine chip-scale cavity optomechanics for acceleration sensing, towards the DC and ultralow-frequency regime and in an integrated chip-scale field modules for precision sensing. Our efforts are described in three integrated Thrusts: (I) Advancements of the chip-scale optomechanical accelerometers through RF readout, including state-of-the-art optomechanical transduction and sensing; (II) Precision measurements in the oscillation regime with DC external acceleration perturbations, including fundamental noise limits; and (III) Integrated precision accelerometer chipsets including detection integration and dynamic range considerations. The project's efforts are realized in integrated chip-scale CMOS modules while offering unprecedented sensitivities and in the DC measurement regime, each supported by our preliminary measurements. The three research Thrusts are integrated with an educational Thrust (IV) focusing primarily on outreach to K-12 students through the Double Discovery Center for first-generation college-bound youth, developing a high-school science curriculum on modern sensors for the Harlem and lower Bronx community, and a new "hands-on" undergraduate and graduate Sensors laboratory.

Non-technical description: The recent discovery of graphene, a material of single atomic thickness, has spurred remarkable advances in condensed matter physics as well as, nanometer-scale device applications covering electronic, thermal and mechanical domains. In chip-scale optoelectronics and optical physics, graphene has a unique optical absorption defined solely by the interaction between light and electrons. This project examines and advances the many-body light-matter interactions in graphene towards optoelectronics, particularly for ultrafast optics, for multi-electron current generation in photodetectors, and for next-generation optical switches and modulators. The research involves laser-material interactions, nonlinear optics, material characterization, and synchronized material-device physics. In parallel and leveraging the fundamental science advanced, the education activity involves outreach to East Los Angeles minority-heavy high-schools and teachers, partnership with the Center for Excellence in Engineering and Diversity for low-income underrepresented first-generation college-bound youth, and a new graduate/undergraduate course on solid-state optoelectronics.

Technical description: The unique linear and massless band structure of graphene, in a purely two-dimensional Dirac fermionic structure, has enabled an optical sheet conductivity that is remarkably frequency-independent, with broadband optical character spanning from visible to mid-infrared wavelengths. The underlying interband optical transitions can be tuned significantly via electric gating near the Dirac point, with a tunable charge-density-based Fermi level due to the low density of sp2-hybridized two-dimensional states. In this project the principal investigator examines the many-body light-matter interactions in graphene optoelectronics covering the electron-electron, electron-phonon, electron-photon scattering mechanisms and dynamics. These interactions are targeted towards device physics and applications in ultrafast optics (first thrust), multi-carrier photocurrent dynamics (second thrust), and electro-optics (third thrust). The first thrust examines all-optical nonlinearities such as four-wave mixing and nonlinear dynamics in graphene: this involves continuous-wave and pulsed measurements, with the gate-tunable Fermi levels in graphene and carrier dynamics. The second thrust examines optoelectronic photocurrent generation in graphene-silicon structures: this involves photocurrent mapping and comparison with monolithic silicon structures, gated-bias carrier dynamics, and hot carrier multiplication in electronic transport. The third thrust examines high-speed electro-optic modulators through interband and intraband transitions: this involves working with carrier frequencies in excess of 100 GHz to even the THz level, supported by Raman characterization and surface phonon engineering. Fermi level tuning, nonlinear signal detection techniques, along with surface material control and processing, are implemented to enable the unique device physics. The many-body scattering dynamics - each at the sub-picosecond timecales - provide a fertile ground for fundamental material and atomic layer engineering studies in graphene-based next-generation optoelectronics.

A chip-scale high-dimensional entanglement and quantum memory module for secure communications

Non-technical: The development of quantum communication with security guaranteed by the laws of quantum physics is one of the major benefits of nonclassical information processing. Using communication bits encoded in quantum states of single photons, called qubits, this project will improve the bandwidth and reliability of quantum communication channels. Advancing the art of quantum communication with photonic qubits is a frontier research topic because although these qubits provide security, the current technology for quantum communication has some limitations. For example, the secure-key distribution rate (akin to the number of qubits per second) and the communication distance can both be improved. These operating parameters are currently around 1 Mb/s for distances around 50 km, hence their rate-distance product is many orders-of-magnitude lower than current classical fiber network communication rates and distances. The team seeks to address this problem via a transformative multi-pronged approach: (1) encoding more bits per photon by using the time-frequency degree-of-freedom; (2) developing a chip-scale photon qubit source for higher rates, higher stability, and easier deployment; (3) developing a chip-scale photon qubit storage and release module for longer distance nonclassical communications; and (4) fundamentally new protocols and architectures for orders-of-magnitude higher secure-key rates. This multi-pronged approach is supported by the team's recent leading advances in these areas, and matched with their pedagogical training and education outreach in chip-scale nonclassical optics. They have an emphasis on women and minority graduate students in their training. Their effort spans the fields of material science, nanofabrication and silicon photonics, quantum measurements, and quantum information theory.

Technical: Quantum entanglement is a fundamental resource for secure information processing and communications, and photonic hyperentanglement or high-dimensional entanglement has been specifically cited in this regard for its high data capacity and error resilience. The continuous-variable nature of time¡Vfrequency entanglement makes it an ideal candidate for efficient high-dimensional coding with minimal limitations. By storing high-dimensional entanglement in quantum memories, the range of entanglement distribution can be extended for long distance quantum communications. While significant progress has been made towards sources of high-dimensional entanglement and long-term quantum memories, major challenges remain in matching the frequencies and bandwidths of these components, integrating them on-chip, room-temperature operation, and developing the theoretical framework for how they can be exploited efficiently. The intellectual significance is to address these challenges and demonstrate a scalable cross-cutting platform towards chip-enabled unbreakable communication networks. The project has three interrelated thematic Thrusts. In Thrust 1, the team methods and approaches will develop on-chip biphoton frequency comb sources and auxiliary devices for quantum communication such as integrated lithium niobate for biphoton production and single-photon frequency conversion, microresonator structures for comb creation, electrically-pumped module, and Franson and conjugate Franson interferometers for security checks. These devices are matched in frequency and bandwidth with the ones in Thrust 2, where the team will develop solid-state rare-earth quantum memories for storage of the high-dimensional biphoton frequency comb, and room-temperature operation via phononic bandgaps and laser refrigeration. In Thrust 3, the team will develop security analyses for new quantum key distribution protocols that exploit the full potential of chip-scale biphoton frequency combs, verified in a full link performance testbed. Thrust III also examines the memories in quantum repeater architectures for distributing entanglement in quantum networks, thus extending the range of high secret-key rate quantum communication. The proposed scientific advances are coupled directly to multidisciplinary education and pedagogical training of underrepresented scientists and engineers in nanoscale quantum information sciences. The PI's interdisciplinary training crosses boundaries in electrical engineering, materials science, information theory and physics, to advance the nanoscale chip-based frontiers of quantum communications.

Recent advances in nanomaterials and device physics have brought about new frontiers in undergraduate education and training. To address these scientific challenges and to significantly broaden outreach to underrepresented minority and women's groups in science and engineering, the University of California-Los Angeles (UCLA) will conduct a REU Site program, An Integrated Diversity Undergraduate Research Experience in Functional NanoMaterials (FNM) in partnership with the Center for Function Accelerated nanoMaterial Engineering (FAME) at UCLA. FAME is a long-standing effective industry-academia partnership, with world-leading research and competencies in unconventional materials and new correlated physics for next-generation device technologies. The REU research projects will focus on world-class unconventional materials and device physics for next-generation um and nm-scale electronics and optoelectronics.

UCLA will host 10 REU students over a 10-week summer program where they will participate in interdisciplinary research projects on functional nanomaterials. Mentoring and cohesive cohort-wide activities will be central tenets to this REU. FNM will implement weekly faculty-student updates and discussions, weekly REU site-wide professional development and cross-training workshops, in addition to external periodic surveys with feedback action items, and a cumulative symposium for the REU scholars.

Chip-scale fT/cm/Hz1/2 optical magnetic gradiometry for gradient magnetoencephalography imaging at room temperature Magnetoencephalography (MEG) provides a direct and non-invasive modality to brain electrophysiological activity, with fundamental measurement principles and signal dynamics highly distinct yet complementary to electroencephalography. Current leading instrumentations such as a superconducting interference device enables remarkable few fT sensitivities, significant for imaging of postsynaptic potentials and about 107 smaller than Earth?s static magnetic field. Operating the superconducting sensor, however, requires liquid helium cryogenics, large-sized insulating dewar tanks, and heavily-field-shielded expensive environments, resulting in specialized imaging centers in the country and hardly portable for frontline diagnostics or wide-spread hospital usage. Objective: here we propose to demonstrate a chip-scale room-temperature magnetic gradiometer with similar sensitivities in unshielded ambient environments, enabled by our gradient approach and our recent laser measurements at the thermodynamical limits. Our gradiometer is based on a laser-driven silicon optomechanical resonant oscillator, combined with static Lorentz-force magnetic field sensing, for optical readout at 1 fT/cm/Hz1/2 sensitivities and 5 fT/cm accuracies at room temperature. Our precise and accurate sensor intrinsically measures the magnetic gradient and has similar performance metrics of the magnetic field energy resolution per unit bandwidth, compared to state-of-the-art superconducting interference devices and optically-pumped spin-exchange-relaxation-free atomic magnetometers. In this R21 exploratory grant, we will demonstrate the ?first light? measurements on the gradiometer, with the three Specific Aims: (1) demonstrating a dual-loop fT/cm/Hz1/2 magnetic gradiometer on- chip and at room temperature; (2) demonstrating gradiometer co-localization with a total field magnetometer, along with RF signal processing; and (3) validation of gradiometer in simulated sources and MEG testbeds.

Wireless communications and networks have experienced exponential growth in data rates and traffic over the past decade, driven by the ever-increasing density of mobile devices, multimedia services and data requirements. The resulting electromagnetic spectrum below 60-GHz has become extremely overcrowded, even with advanced spectrum-efficient modulation formats and spatially diverse multiple-input multiple-output (MIMO) techniques. At present, the sub-millimeter-wave (sub-mm-Wave) electromagnetic spectrum between 300 GHz and 850 GHz is largely unassigned and provides a unique opportunity for more efficient utilization. This will avoid further crowding the currently heavily used spectrum and significantly enhance data rates to tens of Gb/s. This project seeks to demonstrate such a fundamentally new platform towards spectral-efficient and energy-efficient wireless communications with embedded security. Due to the inherent atmospheric attenuation, the sub-mm-Wave communication distance has been limited to within 50 m. Thus, this project proposes network configurations of sub-mm-Wave point-to-point links to enable secured spatial coverage over longer distances and larger areas. There are two distinct differences of the sub-mm-Wave links compared to traditional wireless networks: the directivity of the sub-mm-Wave links and the possibility for a transmitter to connect to multiple receivers through adaptive electronic beam-steering and beam-forming. The beam-forming with narrow beam-width removes broadcasting and avoids interference, enabling much simpler network operation to approach the theoretical upper limits of network information capacity. The project seeks to demonstrate the modular sub-mm-Wave link hardware to achieve the above goal. The proposed research will be complemented with an integrated education and outreach program. This includes diversity recruitment, mentoring and retention, hands-on curriculum development, minority high-school and undergraduate training, and public outreach. The cross-layer scientific and education provides a new platform at the interface of hardware, software, and networks in next-generation wireless communication networks.

This project will develop a spectrally dense, high-data-rate, 650-GHz photonic wireless communications platform in a diamond mesh network, while explicitly addressing network security and energy efficiency in the architecture. The collaborative research spans across the physical layer, the network layer, and the software layer, addressing cross-layer issues in the fundamental architecture. The proposed research consists of three thrust areas. In Thrust I, the project will examine a modular photonic sub-mm-Wave link, based on a chip-scale photomixer driven by an optical frequency comb recently developed by the team. This enables high-power spectrally dense, 80 Gb/s sub-mm-Wave transmission. In Thrust II, the project will examine a photonic sub-mm-Wave 80 Gb/s testbed, implemented with an adaptive smart antenna array. Beam-steering and beam-forming will enable simultaneously a directional line-of-sight (LoS) link and a non-line-of-sight (NLoS) link, with the former establishing a spectrally efficient channel with less inter-symbol and inter-channel interference. The latter mitigates medium non-idealities such as interference, shadowing, and multi-path effects. In Thrust III, the project will study the capacity of sub-mm-Wave communication networks and explore the design of near-optimal efficient and secure algorithms. Enabled by the intrinsic directivity and beam-forming capabilities of our sub-mm-Wave link, the project will advance the possibility of unconditional security in the wireless backhaul network through physical layer security algorithms.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Terahertz spectrometry offers a platform for long-distance and non-destructive detection of trace chemicals and gases, explosives, pathogens, and biological agents. These molecules and hazardous agents have unique absorption spectra in the terahertz frequencies, enabling identification of concealed hazardous substances from remote distances. Heterodyne spectrometers are at the frontier for high spectral resolution terahertz spectrometry. Achieved through a number of different techniques such as nonlinear frequency mixing in Schottky diodes, superconductor-insulator-superconductor structures, or hot electron bolometers, they have linewidth-to-center frequency ratios down to one part in a million. These state-of-the-art heterodyne spectrometers and mixers, however, are bulky (weighing tens of kilograms), are bounded by electronic noise far from the fundamental noise limits, and often require cryogenic cooling to reach appreciable sensitivities. This project proposes a chip-scale terahertz spectrometer based on modular integration of a chip-scale laser frequency comb with a chip-scale photomixer. The laser frequency comb consists of discrete optical frequency lines, widely tunable over an octave. The photomixer is based on a plasmonically-enhanced absorbing substrate, directly coupled to a terahertz antenna to collect the incident terahertz radiation. The proposed single-chip terahertz receiver has spectrometry bandwidth of 1-8 THz with spectral resolution better than a kHz, and operates close to the thermodynamical noise limits. The high-performance, low-cost, and compact terahertz spectrometer brings valuable applications in space sciences, biological analysis, environmental studies, pharmaceuticals, and industrial quality control. The proposed scientific efforts are coupled with an outreach and education plan. This involves outreach to underrepresented high-school students and teachers, improvements to the graduate and undergraduate curriculum, and outreach to the general public with focus on underrepresented women and minority students in summer research experiences for undergraduates.

The proposed advancement on the heterodyne chip-scale spectrometer consists of three cross-related Thrusts. In Thrust 1, the project will demonstrate an on-chip frequency comb oscillator with wide tuning range of 1-8 THz and comb line-to-line non-uniformity at 0.2 parts per quadrillion when referenced to the optical carrier. In Thrust 2, the project will develop an on-chip integrated pump laser and amplifier, for heterogeneous integration with the photomixer and frequency comb. In Thrust 3, the project will demonstrate the integrated chip-scale heterodyne receiver based on an antenna-coupled plasmonic photomixer. The team seeks to measure a heterodyne photomixer with double-sideband noise sensitivities close to the fundamental bound. The frequency-agile approach is enabled by their recent preliminary studies and measurements close to or at the thermodynamical noise limits. The proposed terahertz spectrometry architecture and scientific Thrusts can transform the platform of terahertz waves for atmospheric studies, space explorations, and safety-industrial-environmental quality control systems. The scientific Thrusts are integrated with educational outreach and cross-disciplinary training efforts. This three-year project will educate a new generation of scientists at the interface of precision chip-scale frequency combs and plasmonic photomixers for transformative terahertz spectrometry near the fundamental bounds.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Nontechnical description: Recently there has been intense interest in next-generation quantum cryptography, a communications method immune to eavesdropping, which enables unbreakable secure data sharing. Quantum cryptography is based on the concept of entangled photons, which are uniquely-coupled particles of light. The important property about entangled photons is the ability to gain knowledge about one photon when measuring the properties of the other photon. This uncommon behaviour is unique to quantum particles such as photons, and is at the core of secure quantum information technologies. To date, however, sources that efficiently produce entangled photons have not been fully developed due to lack of appropriate material systems, precision fabrication, or optical characterization approaches. This project overcomes these challenges through advanced photonic materials design and precise nanoscale synthesis of quantum dots in which entangled photons are created. The project activity also embraces the pedagogical efforts for outreach into the undergraduate, underrepresented, high-school and general community, with emphasis on underrepresented students in science and technology. Consistent cross-training of undergraduate and graduate students and new cross-disciplinary curricula development impact the scientific advances at the interface of mesoscopic materials and quantum sciences.

Technical description: The generation of entangled photons is the cornerstone towards quantum communications, where the collapse of the photon wavefunction upon measurement or detection can be detected through channel monitoring. Much of the entangled photon sources, however, are based on spontaneous parametric downconversion. The spontaneous emission process is not deterministic and some degree of photon statistics - whether in Bell inequality measurements or tomography - is still needed, resulting in long-time counting and slow secure key rates. This project aims to tackle the challenge by demonstrating a deterministic entangled photon source based on a hybrid quantum dot-nanowire heterostructure. The first part of this project aims to demonstrate a hybrid quantum dot-nanowire heterostructure by selective area epitaxy for deterministic entangled photon generation. To achieve near-zero fine-structure splitting, the heterointerfaces and the geometry of quantum dots need to be carefully controlled by appropriate growth techniques. The second part of the research seeks to examine the photon correlation and measure the indistinguishability of the entangled photons generated in the mesoscopic solid-state implementation. The project also integrates the research with a pedagogical educational and outreach plan, including innovative outreach, training and mentoring of undergraduates and graduates, and a new graduate course on physics of quantum communication devices. Some examples of activities include hosting summer high school students to experience laboratory work, employing undergraduate students to fully participate in academic research, and developing a new graduate course: Mesoscopic Materials for Quantum Communications.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

The field of quantum information science and technology hinges on unique quantum mechanical phenomena such as entanglement to enable unprecedented capabilities for communication, sensing, and computing. Among these technologies, quantum communication is foreseen to create broad near-term impacts as seen in recent quantum testbeds, teleportation, and entanglement distribution experiments. It is also envisaged to underpin future's fully connected quantum computers, quantum sensors, and a global secure communication network. Mainstream quantum communication platforms, however, rely on expensive, unscalable bulk optics components that impede their widespread deployment. While recent work on integrated quantum communication devices opens a new route to the development of compact quantum-communication systems, an integrated quantum photonics platform encompassing multiple, functional modules on a single chip to generate and process large-scale entanglement remains elusive.
This collaborative project will develop a room-temperature integrated quantum photonics platform that incorporates quantum communication modules for scalable generation, processing, multicasting, and detection of large-scale multipartite entanglement in a quantum communication network. This project will leverage the nanofabrication and testing expertise at UCLA and the Interdisciplinary Quantum Information Research and Engineering (INQUIRE) testbed at the University of Arizona (UA) to demonstrate the capability of utilizing a highly compact and mass producible integrated platform to generate, multicast, and detect large-scale entanglement in a real-world setting. The outcome of the project will lay the foundation for future's quantum internet comprised of compact devices linked by large-scale multipartite entanglement. This project will educate and train the next-generation workforce for quantum information science and technology. Specifically, undergraduate and graduate students will grasp essential knowledge and expertise of nanophotonics and quantum information science and technology. They will gain hands-on experience while undertaking research in the INQUIRE testbed. This project will also provide opportunities for various industrial partners to be exposed to state-of-the-art tools grown out of nanophotonics and quantum information science and technology.

Technical: The team will follow a system-level design approach for the integrated quantum photonics platform. The project will advance knowledge through a new quantum encoding-and-decoding paradigm that will be seamlessly incorporated into a physical architecture to offer intrinsic protection against loss. The physical architecture will consist of programmable quantum sources, processing units, and receivers using the silicon nitride material system that offer dramatic functionalities. Through ��(3 four-wave mixing in microring resonators and Mach-Zehnder interferometers, the silicon nitride chipset section will produce and process quantum signals with high fidelity and low loss. The silicon nitride section will also provide a classical frequency comb to serve as the pump for the microring resonators and phase references for the Mach-Zehnder interferometers. Programming of the quantum sources, processing units, and receivers will be by modulating the classical comb spectral lines in an integrated hybrid silicon section. In our frequency comb cluster system, the quantum signals will be immune to the programming-induced loss and disturbance. The integrated quantum photonics platform will be programmed to support two system-level quantum communication implementations: 1) a high-rate secure communication system based on quantum illumination; and 2) an entanglement multicasting and purification demonstration.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

This proposal requests funds for the "2019 EFRI ACQUIRE Grantees Meeting", the third annual meeting for the NSF-funded Advancing Communication and Quantum Information Research in Engineering (ACQUIRE) program. It will be held this year on September 19-20 in Washington, DC. The goal of this grantees meeting is to review current grantees' research progress, hear about latest international research progress in this area, discuss future research opportunities and challenges and provide feedback to ACQUIRE researchers. The support requested in this grant will be distributed to students to partially defray travel costs, and to help cover a portion of other key logistical and organizational costs. This meeting provides an opportunity for grantees' students to make poster presentations to and get feedback from reviewers, ACQUIRE PIs and invited keynote speakers. The workshop will provide inter-disciplinary interactions between engineering and physics disciplines for enabling student participation and learning opportunities.

The intellectual merit of this grantees meeting is to review current grantees' research progress, discuss future research in the ACQUIRE program, and provide feedback. Engineering and physics researchers are confronting major challenges in a four-year quest to engineer micro-scale quantum communication system components for large-scale networks. The challenging goal is to create a compact and practical quantum communication technology operating near room temperature with low energy in a fiber optic network with entangled photons. A diverse range of topics and techniques are being investigated, including sources, detectors, up-converters, quantum memories, synchronizers, error correctors, etc. with various material platforms. This annual grantees meeting offers an opportunity for recommendations for the ACQUIRE program and future growth of the related and broader topics of quantum optical communications research, and secure optical communications with key researchers and decision makers from academia, industry, government laboratories and funding agencies. In terms of educational aspects, this meeting provides an opportunity for grantees' students to make poster presentations to, and get feedback from reviewers, ACQUIRE PIs and invited speakers. Students will benefit and learn from attending discussions involving different perspectives ranging from university experts and industry scientists. They will also be exposed to diverse aspects of quantum optical communications which bridge traditional physics and engineering disciplines.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

The broader impact/commercial potential of this I-Corps project is the development of precision laser sensing for vehicular navigation and safety. Recently, there has been a substantial commercial effort to build modular light detection and ranging (LiDAR) units to achieve the perception stack of autonomous and robotic-drone platforms. However, most state-of-the-art LiDAR sensors are based on mechanically rotating laser arrays or bulk solid-state lasers that are large, heavy, consume high-power and are difficult to scale. Recent results have demonstrated a chip-scale LiDAR architecture based on on-chip lasers and optoelectronics, enabling a solid-state approach with high performance. In this I-Corps program, the goal is to identify potential customers and market of highest need through the customer discovery process, and to develop a detailed and robust business model.

This I-Corps project is based on the development of precision laser sensing for vehicular navigation and safety and supported by preliminary chip demonstrations in the laboratory. Using this technology, the 3D vehicular surroundings may be mapped via laser time-of-flight reflection. Together with modeling and design parameter analysis, performance of the LiDAR chip has been examined using advances in the photonic design, coupled with advances in the laser precision measurements and thresholds, and detector signal-to-noise ratio. The photonic implementation is scalable through the foundry processing compared to prior studies on bulk rotating laser arrays or bulky solid-state lasers. This chip-scale laser sensing technology may enable the readiness level of autonomous vehicle sensors.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

The broader impact/commercial potential of this Partnerships for Innovation - Technology Translation (PFI-TT) project is the development of a high-precision, chip-scale, laser ranging module, as a key sensing modality in the perception stack. This tool will enable new technological endeavors and sensing capabilities in autonomous vehicles, robotic platforms and other applications requiring high precision knowledge of the environment and surroundings. Light detection and ranging (LiDAR) is a core element for distance ranging and metrology by measuring the light time-of-flight. Recently there have been substantial efforts to build modular LiDAR units. Most current state-of-the-art LiDAR sensors are based on mechanical rotating laser arrays or bulk solid-state laser units that are large, heavy, costly and consume large amounts of power. Recently the UCLA team has demonstrated a chip-scale LiDAR architecture, based on photonics and silicon electronic-photonic integration, in a compact module. The chip-scale electronic-photonic system has state-of-the-art high data acquisition rates and high resolution in sensing the external environment. The team will further develop and implement their commercialization strategy, working with a technology commercialization mentor and early-stage industry partners.

The proposed project examines a new chip-scale LiDAR architecture of pulsed-coherent, segmented, time-of-flight measurement to achieve the high-resolution and high sampling rate. The goal of the proposed research is to achieve a 3D point cloud sensing of the external environment, with scope focused on demonstrating the scalable core components, packaging, and functional prototype. In terms of methodology, the proposed photonics source is based on the unique chip-scale laser element, and readout based on a silicon CMOS technology circuits. The team will co-optimize the photonic and electronic component specifications to achieve a high resolution and high sampling rate demonstration. Detector noise and laser stability will be examined and demonstrated, supported with a technology assessment and risk mitigation approach. This PFI project is aimed at translating the current laboratory demonstration into a commercial sensing prototype, working with end-users and a manufacturing partner foundry towards chip-scale precision navigation and metrology.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

The broader impact/commercial potential of this Small Business Innovation Research (SBIR) Phase I project is to demonstrate a transformative augmented/mixed-reality smart glass to enable new immersive digital spaces. The high-performance implementation of the technology developed here will be used to augment users' perception and understanding of information and images. The remote and virtual human-to-human interactions can be enhanced through these user-natural augment/mixed-reality smart glasses beyond the smartphone. This next-generation mobile display more seamlessly interfaces with online content available today and in already established networks, ranging from online retail, gaming, sports immersion, entertainment, and social networks.

This Small Business Innovation Research (SBIR) Phase I project develops smart glasses for augmented/mixed-reality digital spaces beyond the smartphone. Current smart glasses are typically based on conventional holographic or diffractive optical elements which have significant physical and performance limitations, preventing their wide-spread adoption. This project develops metasurface waveguides to achieve the key performance metrics of resolution, field-of-view, efficiency and optical element integration in augmented/mixed-reality waveguides. The metasurface waveguide is finely tuned for high performance specifications collectively, across the full color gamut, and with ease of fabrication and manufacturing scaling. The system is light weight, compact, and integrates with current light sources.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Secure communication has long been an indispensable part of numerous systems, ranging from the more traditional such as finance and defense to the emerging ones such as the internet of (battlefield) things and health data management. Traditional data encryption methods based on using public keys are threatened by the advances in quantum computing algorithms promising to efficiently solve otherwise intractable problems which make public key encryption secure. However, it is precisely quantum information processing advances that are also expected to enable secure communications by allowing efficient and secure private key distribution. The main advantage of private key encryption is that as long as the key strings are truly secret, it is provably secure, that is, insensitive to advances in computing. A Quantum Key Distribution (QKD) protocol describes how two parties, commonly referred to as Alice and Bob, can establish a secret key by communicating over a quantum and a public classical channel that both can be accessed by an eavesdropper Eve. For the widespread adoption of QKD, it is mandatory to provide high key rates over long distances. What has appeared as a bottleneck in practice is the inability to maximize the utility of information-bearing quantum states. This project seeks to solve this inefficiency problem. The results will pave the way for practical quantum networks in which multiple receivers communicate with a source simultaneously though multi-channel entanglement distribution.

This project focuses on maximizing the utility of photons in frequency-time entanglement based QKD, through a combination of innovations in adaptive photon generation-aware modulation and coding, and a state of the art experimental validation. QKD offers a physically secure way for establishing an encryption key over a quantum and a public communication channel, both of which are observed by an eavesdropper. Because of the growing demand for quantum communications, research on improving QKD protocols has steeply intensified. One recent breakthrough is the experimental observation of continuous-variable frequency-time hyperentangled photons. This high-dimensional large Hilbert-space approach promises high information efficiency by potentially carrying multiple bits per an entangled photon pair. However, to ensure unconditional security in QKD, the biphotons (whether carrying single qubit or multiple qubits per photon), must be transmitted under photon-starved conditions, creating an immediate need to maximize utility of all generated biphotons. The project will offer an integrated solution consisting of photon-aware modulation and coding schemes, and will be the first such to be demonstrated on time-bin encoded multi-dimensional biphotons.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Recent efforts have demonstrated remarkable interconnects between solid-state qubits, atomic qubits, quantum sensing platforms, and solid-state ensembles. This not only provides for the next-generation of scalable compact quantum microprocessors, but also lays the foundation towards a transformative interconnected quantum network for quantum state transfer, sensing, computation, and communications. Advancing from the recent quantum intra-chip interconnects and processors demonstrated by the community, this team leads and advances the interdisciplinary frontier for quantum communications and interconnects – that of distributed entanglement and interconnected quantum networks. This is enabled by the team’s experimental contributions in high-dimensional time-frequency qubits for quantum communications, spin-photon readout of rare-earth ion-based quantum memories towards repeaters in network links, unique error correction algorithms and coding, and fundamental theoretical bounds and numerical computations. The interdisciplinary effort spans across Applied Physics, Chemistry, Electrical & Computer Engineering, Materials Science, Mathematics, and Physics. Working together with our industry and national laboratory colleagues, this team effort allows the examination of interconnected quantum network performance parameters, even in the presence of non-idealities.

This QuIC-TAQS team studies three synergistic Thrusts to establish the cross-foundations towards a chip-scalable Interconnected Quantum Network. In Thrust I, the QuIC-TAQS team examines high-dimensional high-rate quantum photonic transmitters with integrated chip measurements. This includes a 8192-Hilbert space dimensionality in a high-rate link encoding, along with Bell state measurements and low-jitter detection. In Thrust II, the QuIC-TAQS team examines high-fidelity high-efficiency chip-scale quantum memories, in joint measurements between UCLA and Caltech. This is based on solid-state erbium-ions with dynamical control towards network repeaters. Unique protocols and coherence time improvements will be studied. In Thrust III, the QuIC-TAQS team examines robust quantum links, including coding and architecture, to establish a quantum network testbed at UCLA. Supporting the measurements, protocol improvements and numerical simulations of the network performance will be examined. The examined QuIC-TAQS Thrusts spans across integrated quantum photonic platforms, modular quantum sources and memory units, towards a secure interconnected quantum network. The scientific Thrusts of this QuIC-TAQS team is complemented with training of a diverse workforce, with priority emphasis on underrepresented graduate and undergraduate students. This involves recruitment from minority undergraduate and community college research site programs, focused mentorship efforts at UCLA-Colorado-Caltech in quantum science and technology.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Quantum sciences and technologies have progressed remarkably in recent years. This progress includes, for example, new quantum processors with unique computational capabilities, secure channels over metropolitan distances, and unprecedented resolution in fields and force sensing. Continued progress requires the training of a new generation of scientists and engineers to develop these technologies. This National Science Foundation Research Traineeship (NRT) award to the University of California Los Angeles will accelerate these computation, communication, and sensing milestones and their interdisciplinary interfaces by training doctoral students in this nascent field of quantum science and technologies. The program will train 134 doctoral students, including 67 funded trainees, bridging relevant concepts from engineering, physics, materials, chemistry, and mathematics. The traineeship has a particularly strong emphasis on increasing the representation of women and minority students in quantum sciences and technologies through broad yet specific outreach recruitment, mentoring, and retention programs.

The Accelerating Interdisciplinary Frontiers in Quantum Sciences and Technologies (AIF-Q) program consists of four thrusts. These include: (1) atomic qubits and novel chemistry; (2) materials and algorithms towards new forms of computation; (3) optical qubits for quantum simulations; and (4) trapped ions for many-body physics. Spanning these interdisciplinary layers, the traineeship ties together core pillars of heterogeneous materials, microwave spectroscopy, and quantum algorithms. Central to the thrusts and core pillars is interdisciplinary graduate education and research training, guided by the faculty and industry-national laboratory interactions. The integrated training program consists of interdisciplinary three-faculty advising and mentoring through laboratory rotations, new course offerings in interdisciplinary quantum sciences and technologies, distinguished external advisory and internal steering councils, and formative-summative assessments. The program team will pursue seed and joint interactions together with industry and national laboratory partners. A long-term institutional commitment will be embodied in the proposed formation of a University of California Inter-Departmental Degree Program in Quantum Sciences and Technologies.

The NSF Research Traineeship (NRT) Program is designed to encourage the development and implementation of bold, new, potentially transformative, and scalable models for STEM graduate education training. The Traineeship Track is dedicated to effective training of STEM graduate students in high priority interdisciplinary research areas, through the comprehensive traineeship model that is innovative, evidence-based, and aligned with changing workforce and research needs.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.