This PDF file contains the front matter associated with SPIE Proceedings Volume 11389, including the Title Page, Copyright information, and Table of Contents.

Traditional sorbent materials trap all impinging compounds within a certain molecular weight fraction or polarity range until the sorbent capacity is exhausted. Functionality beyond this broad spectrum binary “trap to capacity” capability is left for design of the sampler, scrubber, or filter with which the sorbent is to be interfaced. The Intelligence Advanced Research Projects Activity (IARPA) Ithildin program is developing novel sorbent materials for chemical sampling and storage, enabled by material engineering at the molecular, nanoscale, and mesoscale level of the sorbent itself, independent of the sampler or filter design into which the sorbent is incorporated. Four specific capability enhancements are under development: (1) Selective Sorption (preferential adsorption of target chemicals or chemical classes of interest, while retaining the capability to collect broad-spectrum background); (2) Clutter Rejection (preferential rejection of high-abundance clutter materials, such as water or hydrocarbons); (3) Temporal Fidelity (a capability to activate/deactivate the sorbent material based on various trigger mechanisms); and (4) Remote Indicators (a remotely detectable signature indicative of adsorption of a specific target or target class). This paper describes advances in core sorbent materials (including transition metal carbide, boron nitride, and porous silica and silicon variants), sorbent functionalization, development of engineered hierarchical structures, and novel coatings that enable passive sorbents to function as active samplers. Highlights include biologically-produced Molecular Organic Frameworks (MOFs) used as a gatekeeper layer, porous silicon thin films with hierarchical pore structures, and novel classes of self-immolative polymers used as chemical triggers. Applications to wearable sensors are discussed.

The demand on flexible and stretchable energy harvesting devices is rapidly increasing, driven by the substantial market growth of a wide range of applications including wearables and humane robotics. In this talk, we will demonstrate a deep reactive ion etching based corrugation technique to transform large-scale commercial rigid solar cells with interdigitated back contacts into ultra-flexible and ultra-stretchable cells with negligible degradation in the initial efficiency. The design of the corrugated patterns to achieve the desired performance and characteristics of the solar cells in terms of flexibility, stretchability, specific weight, power output and heat dissipation will be discussed. Finally, the encapsulation of the solar cells for a reliable and mechanically robust performance will be explained.

Ferroic materials such as ferroelectrics and ferromagnets have been widely used as both information storage media and information sensors. A few examples in this regard are ferroelectric/magnetic random access memory, hard disk, and giant magnetoresistance sensors. These memories have both advantages and disadvantages over typical non-ferroic memories such as flash and DRAM in terms of power consumption, size, and speed. Suitability of these memories in edge computing machines will depend on the specific type of applications, required characteristics, and design constraints. In this talk, I will discuss desired memory characteristics suitable for the edge computing platform that need to be physically flexible and bendable. This constraint is especially applicable in the application space of the internet-of-things and it imposes significant fabrication, performance, and energy consumption challenges. Complex oxide-based ferroic materials are one of the best choices in terms of performance and energy consumption. However, the integration of these materials on flexible substrates has remained a daunting challenge due to their flexible substrate-incompatible structures and stringent growth conditions. Motivated by this challenge, we demonstrate a pathway for integrating epitaxial quality, complex oxide ferroelectric memory devices onto flexible substrates [1]. These devices significantly advance the state of the art in all the key device attributes such as switching speed, memory retention, cycling endurance, and operating power. This work also provides an avenue towards combining the rich functionality of spin states in complex oxides, onto a flexible platform for edge computing. I will also discuss the recent advancements in the field of complex oxide ferroic devices in the context of edge computing applications. Acknowledgment: Characterization of layer transferred ferroic materials by scanning probe microscopy is carried out at Argonne National Laboratory and supported by the US Department of Energy, Office of Basic Energy Sciences, Materials Sciences, and Engineering Division. Materials growth carried out at the University of California Berkeley was supported by the Office of Naval Research Contract No: N00014‐14‐1‐0654.

The Controlled-NOT (CNOT) quantum gate associated with single qubit gates is universal for building all quantum circuits. Although CNOTs based on trapped ions and superconducting qubits have become experimentally feasible, the deterministically functioning quantum CNOT gate with photonic qubits will lead to practical realization of quantum computers in a deterministic manner, and will therefore provide an exponential increase in processing power with lowest decoherence time. Based on a previously proposed CNOT model utilizing a quantum cloner (with a fidelity of 78 %), we present in this work our design of the Compact CNOT gate providing a fidelity of 90.31 %, and give physical realization constraints for building CNOT based decomposition of the Toffoli gate and more generalized photonic CⁿNOT gates. The photonic qubits are encoded by circularly polarized single photons and the design of the gate is based on copying the polarization degree of freedom by quantum cloners. Our model is based on spin of electron in a quantum dot embedded in a double sided optical microcavity which behaves like a beam splitter. Circularly polarizing beam splitters, beam splitters, delay lines, photonic circulators, single qubit operations and other photonic devices are used for the design and decomposition. We show that the fidelity of the decomposed CⁿNOT gates is highly dependent on the errors of the non-perfect photonic devices used and more specifically to the theoretical optimal limit of 5/6 of the quantum cloners required for each CNOT in the decomposition.

The dramatic optical property change of optical phase change materials (O-PCMs) allows the realization of tunable optical and photonic devices with enhanced optical functionalities, such as reconfigurable optics, optical switches and routers, and photonic memories. Recently we developed a new class of non-volatile O-PCM, Ge-Sb-Se-Te (GSST), which features unprecedented broadband optical transparency (1-18.5 micron), large optical contrast (dn = 2) and significantly improved glass forming ability. Leveraging the remarkable material property and advanced design methods, we develop a suite of reconfigurable, all-dielectric metasurface optics with unprecedented performance. In one example, a focal length tunable transmissive metalens is demonstrated showing diffraction-limited imaging performance and complete optical function switching during the phase transition, which sets the foundation for ultra-compact, solid-state, tunable meta-optical systems.

Phase change materials (PCM) provide unique optical characteristics, such as a dramatic change in optical refractive index <1, not obtainable from conventional semiconductor optical materials such as Si and InP. Thus, PCMs are being explored to program and reconfigure optical devices to adapt to the sensing needs per the environment. Also, the nonvolatile nature of PCM devices offers system integration without disturbing the sensing. An example of a PCM-based optical device can be a spatial light modulator (SLM) that enables a coded aperture imaging technique to extract spectral signature for remote detection and identification without platform motion. SLMs offer a way to carry out spectral imaging with reconfigurability, which allows signature detection against a spectrally cluttered background. Here, we report on a new solid-state optical modulator device with a SbTe PCM operating in the infrared range and at cryogenic temperatures with excellent switching cycle reliability for the programming of PCM-based optical devices.

I will discuss the development and utility of the application of Global Topology Optimization Networks (GLOnets) to metasurface design. GLOnets are generative neural networks that can generate a distribution of metasurface designs from random noise inputs, and they train by using adjoint variables calculations as terms for backpropagation. With metagratings operating across a range of wavelengths and angles as a model system, we show that devices produced from the trained generative network have efficiencies comparable to the best devices produced by gradient-based topology optimization. Our reframing of adjoint-based optimization to the training of a generative neural network applies generally to physical systems that support performance improvements by gradient descent.

We present the development and validation of a new approach for quantitative functional imaging of human skin based on the machine learning technique for the analysis of the hyperspectral skin images. The considered skin parameters include blood volume fraction, blood oxygenation, melanin content, and the epidermal layer thickness. Additionally, the degree of residual polarization of the reflected light has been analyzed. The validity of the approach has been confirmed by the initial preclinical tests with the tissue-mimicking phantoms, functional in-vivo skin tests, and pilot clinical study of type II diabetic patients. The proposed technique has great potential to be implemented in clinical practice for monitoring and diagnosis of chronic skin ulcers and other relevant diseases.

Point defects in semiconductors are useful as quantum sensors, quantum emitters, and qubits for quantum computation. We have used ab initio quantum chemistry (supercell) calculations to model the photoluminescence of a new vanadium-nitrogen defect in diamond. Using ion implantation, we have attempted to synthesize this defect, and I will present spectroscopic analysis of our sample. Nanoscale positioning of defects is desired to improve the reliable coupling of defect centers to quantum photonic devices. I will discuss the merits of several methods for achieving this: introduction of functionalized seed molecules during diamond synthesis, laser annealing, and ion implantation. I will also present a scalable opto-thermal-mechanical printing method for additively releasing nanoparticles from a donor substrate and transferring them to a target substrate, such as a photonic device. Such integration is a crucial step towards realizing commercially scalable quantum sensing devices.

Measurements from the gas-sensitive nanomaterials typically involve the use of interdigitated electrodes. A separate heater is often integrated for fast recovery. However, their use increases fabrication complexity. Here, a novel gas sensing platform based on a highly porous laser-induced graphene (LIG) pattern is reported. The LIG gas sensing platform consists of a sensing region and a serpentine interconnect region. A thin film of metal coated in the serpentine interconnect region significantly reduces its resistance, thereby providing localized healing in the sensing region. Dispersing nanomaterials with different selectivity results in an array to potentially deconvolute various components in the mixture. Systematic investigations of various nanomaterials demonstrate the feasibility of the LIG gas sensing platform. Taken together with the stretchable design in the serpentine interconnects, the demonstrated system could open new opportunities in bio-integrated electronics.

Free-space, optical time-transfer can synchronize two spatially distant clocks. Currently, Global Positioning System (GPS)-based clock synchronization is a common technique to adjust clocks around the globe to a time standard. GPS-based clock measurements utilize radio signals that travel from GPS satellites to receivers. Electromagnetic signals, like radio waves, that travel through the ionosphere interact with the free electrons that causes signal propagation delay proportional to 1=f² and the total electron content, where f is the signal frequency. Uncertainty in the in propagation delay correlates to synchronization uncertainty. Radio frequency (1 GHz) clock synchronizations use atmospheric models and long integration times to correct for propagation delay uncertainty, however it is challenging to model the ionosphere. By utilizing optical frequencies (100 THz) for clock synchronization, the uncertainty in the propagation delay is reduced by a factor of 10¹⁰ enabling high-performing synchronization without ionosphere corrections. This paper introduces and evaluates the performance of free-space, pulsed laser clock synchronization in a laboratory setting. The pulsed laser synchronization technique is directly compared to a cable and frequency counter-based clock discrepancy measurement. This presentation evaluates the short and long term stability of time transfer between chip scale atomic clocks (CSAC) and compares them to a more stable oscillator.

GTOSat is a 6U CubeSat mission that will pave the way for highly reliable, capable CubeSat constellations and missions beyond low Earth orbit (LEO). GTOSat will study Earth’s dynamic radiation belts, acting as a follow-on to NASA’s Van Allen Probe mission and demonstrating the potential utility of SmallSats for both science and space weather monitoring. While a number of previous CubeSats have studied the radiation belts from LEO, GTOSat will launch into a low inclination geosynchronous transfer orbit (GTO) to directly sample the core trapped particle population. From this orbit, it will measure energy spectra and pitch angles of ~hundreds keV - few MeV electrons and ions, with the primary science goal of advancing our quantitative understanding of particle acceleration and loss in the outer radiation belt. High-heritage instrumentation includes the Relativistic Electron Magnetic Spectrometer (REMS), measuring energetic electrons and ions, and a boom-mounted fluxgate magnetometer (MAG) to provide 3-axis knowledge of the local ambient magnetic field. The GTOSat bus consists of a 6U spin-stabilized structure with a Sun-pointing spin axis. Mitigation of radiation effects is accomplished through a multi-pronged systems approach including parts selection and shielding to reduce the total dose for 1 year on orbit to less than ~30 krad. Communication is achieved via an S-band transceiver, enabling high data throughput through the Near-Earth Network (NEN) and low-latency radiation belt monitoring via the Tracking and Data Relay Satellite System (TDRSS).

Explosive, chemical and narcotic materials, when in the wrong hands, pose an immediate threat to public health and safety. As the nature of these threats become more pervasive and lethal to innocent bystanders and unsuspecting military and law enforcement authorities, there is a growing demand for rapid and effective detection of materials in real-time with a high degree of autonomy and portability at safe distances. In an effort to address this need, ChemImage has been developing novel, adaptable, handheld, short-wave infrared (SWIR) molecular chemical imaging systems for real-time analysis of complex environments, including for detection of hazardous materials (e.g., explosives, chemical warfare agents, drugs of abuse). At the heart of this sensor is the Conformal Filter (CF), which is a liquid crystal based tunable filter (LCTF) that transmits multi-band waveforms that mimic the functionality of a discriminant vector for classification of target threats amongst background clutter. Real-time detection (≥10 detection fps) is achieved by operating two CFs in tandem within a dual polarization (DP) system, allowing for simultaneous acquisition of the compressed hyperspectral imaging data. This paper will focus on the development, characterization and testing results of a prototype handheld DP-CF sensor. Details of the autonomous, low size, weight and power (SWaP) sensor and applications of the technology to address realworld detection challenges including High Throughput Mail Screening (HTMS) and Chemical Warfare Agent (CWA) surveying and mapping will be discussed.

The ability to rapidly detect hazardous airborne chemicals with high fidelity in a single point-detection system remains a significant challenge in a complex chemical background. Traditional Gas chromatography (GC) can significantly augment most detection technologies by separating complex mixtures for high fidelity detection, but with the disadvantage of requiring detection at the end of the GC column which adds a time disadvantage for any decision making process. Microfabrication of GC columns has reduced device footprint and power consumption, but the end-of-column detection paradigm remains. We present a rapid detection concept of in-column detection by probing the GC stationary phase which is coated on an IR transparent column substrate. The optical evanescent field interactions in the mid-infrared spectral region (US. Patent# 9,599,567) allows analyte detection along the column without having to wait for complete elution. These spectral signatures, collected at different points along the column, are analyzed by an algorithm to quickly identify components in a complex mixture. We present results with an ATR-based system that uses a focused tunable quantum cascade laser beam directed by galvo mirrors at points along a molded micro-GC column whose base comprises an optically transparent material coated with the stationary phase.

Spectropolarimetry is a powerful technique for remote sensing of the environment. It enables the retrieval of particle shape and size distributions in air and water to an extent that traditional spectroscopy cannot. SPEX is an instrument concept for spectropolarimetry through spectral modulation, providing snapshot, and hence accurate, hyperspectral intensity and degree and angle of linear polarization. Successful SPEX instruments have included groundSPEX and SPEX airborne, which both measure aerosol optical thickness with high precision, and soon SPEXone, which will fly on PACE. Here, we present a low-cost variant for consumer cameras, iSPEX 2, with universal smartphone support. Smartphones enable citizen science measurements which are significantly more scaleable, in space and time, than professional instruments. Universal smartphone support is achieved through a modular hardware design and SPECTACLE data processing. iSPEX 2 will be manufactured through injection molding and 3D printing. A smartphone app for data acquisition and processing is in active development. Production, calibration, and validation will commence in the summer of 2020. Scientific applications will include citizen science measurements of aerosol optical thickness and surface water reflectance, as well as low-cost laboratory and portable spectroscopy.

Miniaturised biomedical implants, such as neural stimulators and leadless pacemakers are becoming increasingly popular. As of yet, access to a reliable power source has been one of the major obstacles towards creating miniature devices with extended functionalities. Batteries tend to take up 80% room while offering a limited lifespan. Moreover, transcutaneous energy transfer systems (TET) designed to deliver power to implants without a physical link require a receiving coil that requires a generous real estate. This research proposes a new transcutaneous energy transfer (TET) method to deliver power to miniaturised deeply implanted biomedical devices.

In this paper, standard top-down fabrication process has been employed to develop GaN nanowires and functionalize by three different metal oxides, such as- TiO₂, ZnO and SnO₂ for comparative analysis of NO₂ gas detection. The gas sensing results indicated that the TiO₂ functionalized GaN exhibited the highest sensing performance toward our target gas at room temperature. The response-recovery process of these metal-oxide/GaN sensor devices has been analyzed here for various gas concentrations. The obtained experimental results were comprehensively explained by modeling with first-principles calculations based on density functional theory (DFT). All the modeling and calculations of metal-oxide/GaN structures in contact with NO2 molecule were performed in BURAI, a GUI of Quantum Espresso software. The adsorption properties and electronic structures (TDOS and PDOS) of these oxide functionalized GaN have been investigated to analyze the charge transfer process of actual sensor devices. In addition, the environmental humidity effect on the TiO₂/GaN device has been investigated experimentally and discussed under the light of DFT calculations.

There are many applications which require high sensitivity spectral detection. In some cases, you need the wavelength range to be extended to cover all necessary spectral fingerprints. We are proposing a broadband spectrometer for ultrasensitive detection based on plasmonic hyperbolic metamaterials and diffraction gratings. Using variety of materials in fabrication of the hyperbolic metamaterials, we can cover the wide spectral range from near UV (~250 nm) to IR (~2 μm). In our spectrometer, the diffraction gratings have two functions. One is coupling the incident light source with the plasmonic guiding modes, which have a very high effective refractive index (≥8.1), much higher than the refractive index of germanium (4.05), the natural material with the highest refractive index. While a prism can also be used for coupling guiding modes with incident light, a diffraction grating is the only way to excite the guiding modes because of the plasmonics modes with very high effective refractive index. The second function of the diffraction gratings is their natural role in spectrometers. We demonstrated based on numerical simulations that we could reach high detection spectral sensitivity using compact diffraction gratings combined with hyperbolic metamaterials; the huge “n-meter” spectrometer is not necessary.

We present a new sensor design of a polymer-based Fiber Bragg Grating (FBG) on a D-shaped optical fiber for detection of variation of temperature and strain. The gratings are molded and are at the proximity to the fiber core, which is made by fiber-assisted UV lithography. The process is suitable for generating optical fiber-based sensors with high repeatability in simple processes. The proposed sensor can be multiplexed, so an array of the proposed sensors will be suitable in detecting a wide range of environmental conditions.

We demonstrate a compact, portable and reliable, poor-man’s 8-channel interconnect and measure, in the 50- 100MHz VHF radiofrequency range, the path-dependent voltage transfer function across drop-cast poly(3,4- ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). The setup may be inexpensively deployed for single-input-multiple-output (SIMO) self-sensing materials with computational impedance tomography algorithms. We test our setup with PEDOT:PSS samples that are dried in a static magnetic field. These samples exhibit anisotropic electrical conductivities and nanostructure morphologies. Voltages across the sample vary 2dB as a result of this anisotropy. This processing-dependent anisotropy of PEDOT:PSS may be useful in future efforts aimed at deconvolving the path-dependent electrical tomography measurements, as necessary for such a sensing system.

Methane is a major composition of natural gas and considered as a primary greenhouse gas of high global warming potential. In addition, it is also a hazardous flammable gas turns out to be highly explosive if its concentration level reaches 5 to 15 percent by volume. Carbon dioxide is another significant gas since CO2 corrosion is the most common cause of corrosion in natural gas pipelines. Long distance cost-effective CH4 and CO2 distributed sensing technologies for monitoring natural gas infrastructure are not yet readily available, and early corrosion on-set and low-level methane leak detection is highly desirable that can strengthen the integrity and operational reliability, improve the efficiency, and reduce pipeline emissions, which all advance the economics of natural gas delivery. In this work, two types of gas sensing materials, porous silica and hybrid polymer/metal-organic framework (MOF), are investigated based on evanescent wave absorption sensors consisting of a coreless fiber spliced between two single-mode fibers. The low-loss, low refractive index porous silica and the polymer/MOF material with an improved gas adsorption capability and CH4/CO2 selectivity prepared by the sol-gel dip-coating method are respectively used as coating applied to the surface of the coreless fiber. The effects of optical and morphological properties on the repeatability and sensitivity of fiber-optic evanescent wave sensors are studied from transmittance and reflectance measurements by utilizing laser diodes operating at CH4 and CO2 absorption lines. Distributed fiber gas sensing can benefit from the enhanced evanescent wave light scattering in the porous materials.

The purpose of the research is to study the novel structure metal-insulator-metal (MIM) rectified antenna (rectenna) and its efficiency for optical frequencies mixing and rectification. Semiconductor diodes have many imperfections such as heat problem and slow response, while MIM devices have less heat problem issues and have response times in the order of femtoseconds.