Polycrystalline lead selenide thin film has now emerged as a promising choice for low-cost and uncooled MWIR detectors and arrays operating at room temperature within the 3~5 µm wavelength range. LCDG (Laser Components Detector Groups) has successfully fabricated a new version of PbSe thin films using the chemical bath deposition (CBD) method on quartz substrates, enabling the development of infrared detectors and arrays with robust and high production yield. To achieve efficient activation of the PbSe thin film, LCDG investigates PbSe material from chemical reaction of the bath deposition to final packaging to meet various customer specifications and establishes PbSe detectors based on nano- and micro-particles embedded PbSe thin film, resulting in exceptional MWIR photoconductive response at room temperature. The characterization of PbSe thin film reveals the presence of various nanostructures, such as nano- and micro-particles as well as Pb-oxide phases and Pb-iodine phase carrier transporting channels. This paper reports the MWIR performance of the uncooled LCDG’s PbSe detector, focusing on responsivity, EQE, 1/f noise and FTIR spectral response (77K-340K), and D*.
Here we investigated the role of oxygen sensitization temperature on physical properties of PbSe thin films. Polycrystalline thin films were deposited on quartz substrates using CBD method and sensitized at different treatment temperatures in an oxygen atmosphere. High temperature sensitization induces fusions/aggregations of individual PbSe grains and forms PbO and SeO2 phases in PbSe matrix. Carrier mobility sensitized at a high temperature increased by ~500 times, in comparison with the sample sensitized at a lower temperature. This mobility improvement could be attributed to the surface, dislocation and defect passivation effects via oxygen diffusing into PbSe and occupying Se vacancies.
We compared spectral response of a PbSe thin film photoconductor using FTIR with either a current or voltage preamplifier from 77K to 340K. The voltage preamplifier had a series load resistor; the current preamplifier did not. A photoconductor’s resistance changes with incident light, thus its measured response in terms of amps or volts per watt of incident light depends on the preamplifier circuit configuration. However, commercial descriptions of spectral response often only present data for a single circuit configuration. This leads to different “apparent” spectral response curves for different circuits with the same device. We investigated how accurately we could predict the response trend of a voltage preamplifier circuit or a current preamplifier circuit using dark resistance (Rdark) and light resistance (Rlight) measurements. We were able to predict the temperature at which maximum response occurs within ~25K, suggesting that this approach can be useful to predict the response of a PbSe photoconductor in various circuits with a limited set of measurements.
We present a design of a quantum information processing C-phase (Controlled-phase) gate applicable for generating cluster states that has a form of integrated photonic circuits assembled with cascaded directional couplers on a Ti in-diffused Lithium Niobate (Ti-LN) platform where directional couplers as the integrated optical analogue of bulk beam splitters are used as fundamental building blocks. Based on experimentally optimized fabrication parameters of Ti-LN optical waveguides operating at an 810nm wavelength, an integrated Ti-LN quantum C-phase gate is designed and simulated. Our proposed C-phase gate consists of three tunable directional couplers cascaded together with having different weighted switching ratios for providing a tool of routing vertically- and horizontally-polarized photons independently. Its operation mechanism relies on selectively controlling the optical coupling of orthogonally polarized modes via the change in the index of refraction, and its operation is confirmed by the BPM simulation.
KEYWORDS: Algorithm development, Software development, Space operations, Situational awareness sensors, Data communications, Standards development, Sensors, Prototyping, Information assurance, Data modeling
The Joint Space Operations Center (JSpOC) Mission System (JMS) is a service-oriented architecture (SOA) infrastructure with increased process automation and improved tools to enhance Space Situational Awareness (SSA) performed at the US-led JSpOC. The Advanced Research, Collaboration, and Application Development Environment (ARCADE) is a test-bed maintained and operated by the Air Force to (1) serve as a centralized test-bed for all research and development activities related to JMS applications, including algorithm development, data source exposure, service orchestration, and software services, and provide developers reciprocal access to relevant tools and data to accelerate technology development, (2) allow the JMS program to communicate user capability priorities and requirements to developers, (3) provide the JMS program with access to state-of-the-art research, development, and computing capabilities, and (4) support JMS Program Office-led market research efforts by identifying outstanding performers that are available to shepherd into the formal transition process. In this paper we will share with the international remote sensing community some of the recent JMS and ARCADE developments that may contribute to greater SSA at the JSpOC in the future, and share technical areas still in great need.
The research detailed in this paper describes a Periodic Cluster State Generator (PCSG) consisting of a monolithic
integrated waveguide device that employs four wave mixing, an array of probabilistic photon guns, single mode
sequential entanglers and an array of controllable entangling gates between modes to create arbitrary cluster states.
Utilizing the PCSG one is able to produce a cluster state with nearest neighbor entanglement in the form of a linear or
square lattice. Cluster state resources of this type have been proven to be able to perform universal quantum
computation.
The fabrication and characterization of a 1×4-element integrated beam former based on electro-optic (EO) polymer phase modulators (PM) is summarized including findings related to waveguide loss, near-, and far-field diffraction patterns. Based on this device, two alternate designs are proposed to improve performance: an unequally spaced 1×4- element and an equally spaced 1×8-element beam former both based on EO polymer PMs. Models of these alternative designs indicate that waveguide propagation loss and strong grating lobes, both of which degraded the performance of the initial device, can be substantially improved. The proposed approach explored by the 8-element beam former introduces novel components including strain-induced optical waveguides, hybrid integration of active and passive polymers, modified waveguide diffraction aperture, and directional coupler thermo-optic (TO) switches.
Optical phased arrays are promising candidates for both RF signal processing and optical beam forming and steering.
These platforms not only enable accurate electrically controlled beam steering at high frequencies but also have the
potential to significantly improve the performance of future free-space optical communications systems. In this work we
exploit recent advancements in both nano-scale hybrid silicon-slot waveguides and electro-optic (EO) polymers to
demonstrate an integrated optical phased-array antenna. Specifically, we create a hybrid integrated "photonic circuit"
that connects an array of optical phase modulators, fed by a common optical signal and a 1x4 splitter, to a compact
optical waveguide diffraction array for optical beam steering applications. The fundamental characteristics of the
resulting integrated optical beam former, including the optical insertion loss, driving voltage, and phase control from the
waveguide aperture are summarized in this letter.
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