This PDF file contains the front matter associated with SPIE Proceedings Volume 11388, including the Title Page, Copyright information, and Table of Contents.

Graphene-HgCdTe heterostructure based mid wave IR (MWIR) detectors are being designed for NASA Earth Science applications. Combining Density Functional Theory (DFT) based calculations of the bandstructure with carrier generation and transport model of this detector, we study the essential physics of this novel detector design and project its performance. Combining the best of both these materials can yield high performance and superior detection capabilities.

Under the DARPA WIRED program, DRS advanced CQD film detectors, deposited by spin-coating from solution directly on readout integrated circuit (ROIC) wafers at room temperature. Such CQD fabrication can produce very small pixel pitch photodiode detectors, which need ROICs with proportionally small pixel pitch readout arrays fabricated on wafers in fully compatible CMOS process. CQD fabrication allows for very large format FPAs, limited only by the ROIC size. This paper presents CMOS ROIC detailed design ready for tapeout of a 3 μm pitch 1920 x 1080 fully optimized for low power and noise in battery powered portable applications. Although the ROIC was designed for CQD detector photodiodes, it could also be used with other 3 μm pitch IR detectors, such as the InGaAs type. Capacitive trans-impedance amplifier (CTIA) pixel was designed using ITAR-compliant 0.13 μm CMOS process. This particular 0.13 μm CMOS process was selected for CTIA pixel due to compact metal design rules for 3 μm pitch, high Gm, low FET noise and availability of high-density metal-insulator-metal (MIM) capacitor. The 3 μm pitch CTIA pixel has 22 Ke- well capacity and input-referred 37 e- or 48 e- readout noise, with and without correlated double sampling (CDS) respectively. The ROIC using 3 μm pitch 1920 x 1080 pixel array was designed to operate in ripple readout mode, both with and without the off-chip CDS. Pixels and single-slope 12 bit column A/D converter achieve < 1% non-linearity over 600 mV pixel output swing, with all necessary biases internally generated. Custom static random access memory (SRAM) is used for storing A/D conversion results with all timing clocks also internally generated. The data from the SRAM is serialized and readout through 4 x 600 Mbps LVDS serial outputs synchronized to 2 LVDS output clocks (2 data and 1 clock output on top and the bottom). The ROIC total power consumption was simulated at 536 mW from 1.2 V and 3.3 V power supplies. The FPAs using 3 μm pixel pitch ROIC and detector can be used in portable applications for atmospheric haze penetration, camouflage and NIR/SWIR designator detection. Such cost-effective targeting cameras can have around 10 hour operating time on single charge from 5000 mA-h, 3.8 V commercial Li-ion battery in portable applications.

Fresnel reflections at boundaries between layered media can be suppressed using anti-reflective randomly-nanostructured surfaces (rARSS). Previous studies have shown that rARSS can result in spectral broadband transmission enhancement and polarization insensitivity, in the specular direction, compared to unstructured optical windows. However, specular reflectance can be suppressed through scattering mechanisms, resulting in an angular redistribution of the reflected irradiance. In those cases, specular transmittance is adversely affected as well. We characterized ZnS, ZnSe, and GaAs windows with rARSS treatment on both surfaces, by measuring the specular transmittance and reflectance, as well as, the directional angular reflective scatter, in the mid-wave and long-wave infrared bands (2 - 12 μm). The incident light was directed off-normal incidence, and the angular reflectance distribution was measured over a ±30° cone, centered on the specular reflection angle. An accurate determination of the redistribution of the reflected energy was obtained, by comparing the scatter of the structured surfaces to the pre-processed, optically flat, substrate performance. Surface roughness was determined using a UV-confocal microscope and a scanning electron microscope. The rARSS feature dimensions were correlated to the overall optical performance. The results show reflective specular and scatter intensity suppression, along with specular transmission enhancement.

We present pre and post space flight test results of 2.2 micron InGaAs Photodiode and GaAs Transimpedance Amplifier (TIA), Optical Receivers that flew to the International Space Station (ISS) as part of the Materials International Space Station Experiment 9 (MISSE-9) payload. The two optical receivers having two different RF packages exhibit bandwidth of 9 GHz or more, and were fiber coupled with a single mode fiber. They were launched in April 2018 to the ISS, and returned to Earth in June 2019 for a cumulative time period of over 13 months. During their time on the ISS, we noted the entry and exit points into the South Atlantic Anomaly (SAA) on a daily basis, and thus, recorded the total time the Extended InGaAs Optical Receivers were exposed to it. It has been shown that the exposure to heavy ions and protons, especially during the SAA transit, cause the most failures to electronic components. We also recorded the daily temperatures they were exposed to during their stay on the ISS, as well as the cumulative radiation dose they experienced through a dedicated dosimeter placed in close proximity to the devices. After analyzing the pre and post flight data on dark current, quantum efficiency, bandwidth, bit error rate, and other 14 different parameters, we did not observe any major degradation in the two device’s performance. Additionally, both RF packages, did not suffer any damage due to the mechanical shock and vibration of the space flight, including the launch and return to Earth.

Northrop Grumman (NG) is developing a photonic waveguide-based imaging spectrometer that promises to dramatically reduce instrument size, weight and power and enable image acquisition in modes not possible with current hyperspectral imagers (HSIs). The objective of our current effort is to develop this novel hyperspectral technology for eventual application to the NASA Sustainable Land Imaging (SLI) mission. For more than 40 years the Landsat program has provided the Earth science community with highly accurate global multispectral imagery (MSI) to monitor our planet and ecosystems. Through extensive modeling and simulation NG has demonstrated that a versatile HSI sensor can meet the goals for a sustainable land imager. Our photonic spectrometer represents a step forward for hyperspectral imaging, providing a path to an extremely compact instrument that will provide fully co-registered spectral and spatial data across the instrument’s field of view.

Sub-wavelength structured planar lenses known as metalenses are leading to a fundamental breakthrough in optical design with the emergence of high-end and multifunctional flat optical components that circumvent limitations in refractive optics. I will introduce our recent advances in broadband high-efficiency metalenses showing an average efficiency of approximately 90% for a wavelength bandwidth of 470 nm to 700 nm. Additionally, using metalenses as an essential core element in optical systems for polarization imaging and achromatic imaging is discussed.

Many large image processing and data processing scenarios can soon develop into maze problems requiring, say, finding the longest possible path, which are unresponsive, intractable, and challenging to analyze! Such maze problems, of which the traveling salesman decision problem is a special case, are of the Non-determinate Polynomial (NPcomplete) class of problems that are often impossible to solve with finite time and storage. We propose a novel methodology to approach this class of NP-complete problems. We convert a suitably formulated maze problem into a Quantum Search Problem (QSP), and the desired solutions are then sought using the iterative Grover’s Search Algorithm. Thus, we reformulate the entire class of such NP-problems into QSPs. Our current solution deals with two-dimensional perfect mazes with no closed loops. We encode all possible individual paths from the starting point of the maze into a quantum register. A quantum fitness operator applied to the register encodes each qubit with its fitness value. We propose the design of an optical oracle that marks all entities above a certain fitness value and uses the Grover search algorithm to find the optimal marked state in an iterative manner.

High voltage electrical failures are dangerous and costly events in any type of power system. The troubleshooting and diagnostic time required to identify and locate these failures can be significant. Partial discharge is one of the early warning signs for electrical degradation. In insulation systems, partial discharge typically occurs in voids located within the dielectric, at material interfaces, or along energized electrode surfaces. Effective methods for finding this failure precursor enabling circumvention of future catastrophic events are highly valuable as successful detection can improve safety, reduce service interruptions, and result in significant financial savings. Challenges arise when these events are obstructed from a direct line of sight (which is common in compact electrical systems). Conventional electrical partial discharge measurements capable of diagnosing concealed defects based on phased resolved partial discharge (PRPD) patterns require coupling devices physically connected to the circuit. This paper presents a non-invasive, real-time, method to detect and locate partial discharge and faulty insulation with potential for automated quality control of in-factory manufactured products and in-service operational devices, in contrast to post-failure assessment. This paper will cover both Alternating Current (AC), previous research, and Direct Current (DC), new research, detection methods and results.

METimage will be the Visible/Infrared Imaging mission (VII) of the METOP-SG series. It is going to provide moderate ground resolution optical imaging of clouds, aerosols and surface variables in 20 spectral channels ranging from 443 to 13 345 nm with a spatial sampling of 500 m. The METimage instrument is in development by an industrial team led by Airbus Defence and Space GmbH on behalf of the German space administration DLR with funding from the German Federal Ministry of Transport and Digital Infrastructure (BMVI) and co funding by EUMETSAT under DLR Contract No. 50EW1521. In the context of this program Hensoldt Optronics GmbH designs, integrates and tests novel multispectral filter assemblies and refractive relay infrared optics for the METimage instrument. Both assemblies have to deliver optical performance in cryogenic-vacuum conditions post launch and deployment loads, which is a challenging demand. The development led to intricate glue-free mounting designs for filters and lenses. To establish the system’s optical performance a combination of prototyping, optical simulation, ambient adjustment and cryogenic-vacuum verification is necessary. For the latter a hexapod-carried OGSE was developed, capable to illuminate and sensing wavefront errors at multiple MWIR and LWIR wavelengths. This paper provides insights into the opto-mechanical designs of the relay optics and the hyperspectral filters. Furthermore the setups for adjustment and qualification tests will be described. The current project progress is reflected here within.

The structure of a silicon avalanche photodiode (APD) has a significant impact on the probability of light creating charge carriers and on the generated noise due to the multiplication process or excess noise factor (ENF). In this paper, we will review front-illuminated and back-illuminated APD structures and their impact on ENF as a function of wavelength from 400 nm to 1000 nm for recently commercially produced silicon APDs targeting LIDAR and other applications. The experimental setup developed for characterization will be described and highlight the differences between the studied structures. APDs with different junction profiles were produced and measurement of ENF was found to match McIntyre’s theory for experimental k-factors (ratio of the hole impact ionization rate to that of electrons) ranging from approximately 0.05 to 0.008. The generated illuminated noise as a function of responsivity can be used as a guideline to select the APD achieving the best signal-to-noise ratio (SNR) for a given application. To help meeting this condition, optimizing the electrical field profile of an APD and making certain the electrons are the primary carriers initiating the avalanche is critical.

Here we elaborate on the edge-enhanced spectral components that are produced by the vortex Fourier trans- form, which are introduced in [1]. The vortex phase pattern imprinted on from an object breaks the spatial invariance of its Fourier representation is robust to noise. We report on new results related to the image classification of the MNIST digit dataset with no hidden layers. We show that the accuracy from one phase vortex mask is capable of achieving 0:95 validation accuracy and further show that the dynamic range of the phase modulation scheme significantly influences the classification accuracy and classification convergence rate.

Calculations are presented of vibrational absorption spectra for isolated molecules of nitorsamines using density function theory (DFT). These contaminants are among widely spread carcinogens in the environment of industrial countries. DFT calculated absorption spectra of isolated molecules represent quantitative estimates that can be correlated with additional information obtained from laboratory measurements. The DFT software GAUSSIAN was used for calculating the infrared (IR) spectra presented here. DFT calculated spectra can be used to construct templates, which are for spectral-feature comparison, and thus detection of spectral-signature features associated with target materials.

The Christiansen Effect occurs when the refractive index (η) of a given material matches that of its surrounding medium at a particular wavelength, leading to a transmission window. When air is chosen as the medium, the Christiansen Effect is observed when the refractive index of a given material passes through η=1 at a specific wavelength (λ), thereby matching that of air, and subsequently producing a transmission at wavelength (λ). In general, materials that exhibit a refractive index of η=1 in the near infrared are of particular interest for a variety of glass optics and imaging applications. In this paper, spectroscopic ellipsometry (SE) is used to determine the complex refractive index of bulk Indium Tin Oxide (ITO) in the near Infrared (IR) and shortwave IR region. This work utilizes the SE results and optical reflectance measurements to demonstrate the utility of using bulk indium tin oxide (ITO), in combination with air, as a means of generating and tuning the Christianson Effect within the near infrared region. Colloidal suspensions of ITO particles produced from the bulk wafers were also studied to explore the Christiansen effect for obscurant applications.