Laser Integration on Silicon Photonic Circuits Through Transfer Printing

New fabrication approach allows the massively parallel transfer of III-V coupons to a silicon photonic target wafer.

The purpose of this project was to develop a transfer printing process for the massively parallel integration of III-V lasers on silicon photonic integrated circuits. Silicon has long offered promise as the ultimate platform for realizing compact photonic integrated circuits (PICs). That promise stems in part from the material's properties: the high refractive-index contrast of silicon allows strong confinement of the optical field, increasing light-matter interaction in a compact space—a particularly important attribute for realizing efficient modulators and high-speed detectors.

Posted in: Briefs, TSP, TSP, Aerospace, Photonics, Integrated circuits, Lasers, Integrated circuits, Lasers, Fabrication, Materials properties, Semiconductors
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High Energy Computed Tomographic Inspection of Munitions

Inspection system provides additional level of quality assurance for R&D, reverse engineering, and malfunction investigations.

An advance computed tomography (CT) system was recently built for the U.S. Army Armament Research, Development and Engineering Center, Picatinny Arsenal, NJ, for the inspection of munitions. The system is a charged coupled device (CCD) camera based CT system designated with the name “experimental Imaging Media” (XIM). The design incorporated shielding for use up to 4MeV x-ray photons and integrated two separate cameras into one single field of view (FOV). Other major distinguishing characteristics include its processing functions to digitally piece the two cameras together, use of advanced artifact reduction principles, performing reconstruction simultaneously during acquisition, and its development in accurate beam hardening corrections through digital means.

Posted in: Briefs, TSP, TSP, Aerospace, Photonics, Charge coupled devices, Imaging, Imaging and visualization, Charge coupled devices, Imaging, Imaging and visualization, Defense industry, Inspections, Missiles
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Development of Photoacoustic Sensing Platforms

Research focuses on sensor miniaturization and detection of chemical targets both proximally and at range.

In recent years, photoacoustic spectroscopy (PAS) has emerged as an attractive and powerful technique well suited for sensing applications. The development of high-power radiation sources and more sophisticated electronics, including sensitive microphones and digital lock-in amplifiers, have allowed for significant advances in PAS. Furthermore, photoacoustic (PA) detection of IR absorption spectra using modern tunable lasers offers several advantages, including simultaneous detection and discrimination of numerous molecules of interest. Successful applications of PAS in gases and condensed matter have made this a notable technique and it is now studied and employed by scientists and engineers in a variety of disciplines.

Posted in: Briefs, TSP, TSP, Aerospace, Photonics, Amplifiers, Electronic equipment, Lasers, Sensors and actuators, Spectroscopy, Amplifiers, Electronic equipment, Lasers, Sensors and actuators, Spectroscopy, Acoustics, Acoustics
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Multi-Channel Laser Absorption Spectrometer for Combustion Product Monitoring

This instrument can detect fires associated with electrical wiring and electronics packaging materials.

NASA’s Jet Propulsion Laboratory, Pasadena, California

Tunable laser absorption spectrometer (TLAS) sensors enable gas monitoring with high accuracy and gas specificity, and can be optimized for continuous, maintenance-free operation on long-duration manned spacecraft missions. This innovation is a portable, five-channel TLAS instrument designed to continuously monitor ambient concentrations of carbon monoxide, hydrogen chloride, hydrogen cyanide, hydrogen fluoride, and carbon dioxide, with low-level detection limits below the standard spacecraft maximum allowable concentrations. Monitoring of these particular hazardous compounds allows tracking of ambient conditions and enables detection of fires associated with electrical wiring and electronics packaging materials.

Posted in: Tech Briefs, Briefs, TSP, Imaging, Photonics, Spectroscopy, Spectroscopy, Life support systems, Gases, Fire detection, Hazardous materials, Spacecraft
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Thermal Cycle Qualification of Radiated Solar Arrays for 50 to 133 K Temperatures in Vacuum

A closed loop system needs no liquid helium.

NASA’s Jet Propulsion Laboratory, Pasadena, California

Solar arrays (radiated or non-radiated) and other technologies are candidate materials for projects in JPL. Some of the projects need to qualify these potential technologies to cryogenic extreme temperatures (from 133 to 50 K or lower). Those technologies need to survive for more than 120 thermal cycles in a thermal vacuum environment to meet three times mission life of the ECM project per JPL design principles. There is not any published thermal cycling qualification data for solar arrays in vacuum to those of cryogenic temperatures. Therefore, an experimental assessment study was undertaken on behalf of the JPL pre-project office for the proposed Europa Clipper mission.

Posted in: Briefs, TSP, Imaging, Photonics, Solar energy, Thermal management, Thermal management, Thermal testing
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Web-Based Search Service to Support Imaging Spectrometer Instrument Operations

An adaptive matched-filter approach compensates for the context and background characteristics of each scene.

NASA’s Jet Propulsion Laboratory, Pasadena, California

Imaging spectrometers yield rich and informative data products, but interpreting them demands time and expertise. There is a continual need for new algorithms and methods for rapid firstdraft analyses to assist analysts during instrument operations. Intelligent data analyses can summarize scenes to draft geologic maps, searching images to direct operator attention to key features. This validates data quality while facilitating rapid tactical decision-making to select follow-up targets. Ideally, these algorithms would operate in seconds, never grow bored, and be free from observation bias about the kinds of mineralogy that will be found.

Posted in: Briefs, TSP, Imaging, Photonics, Mathematical analysis, Internet, Spectroscopy, Internet, Spectroscopy, Data management
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Hermetic Phototube Housing

Goddard Space Flight Center, Greenbelt, Maryland

This innovation is a hermetically sealed case or very small chamber. A photomultiplier tube (PMT) is mounted inside the chamber. The circuit board is also installed inside the chamber with appropriate feedthroughs for signals. An adapter/floating mount called the phototube to light pipe system mount (PLPSM) allows the hermetic PMT housing to attach to the light guide.

Posted in: Briefs, TSP, Imaging, Photonics, Containers, Mountings
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Design, Fabrication, and Test of WFIRST/AFTA GRISM Assembly

Goddard Space Flight Center, Greenbelt, Maryland

This work originated with the Wide Field InfraRed Survey Telescope (WFIRST) slitless spectrometer design (GRISM assembly), which attempted to follow the Hubble Space Telescope (HST) method of employing a singleelement GRISM as a slitless spectroscope. However, WFIRST’s field of view (FOV) is ~100x of HST’s wide field camera, and the spectral resolution is ~5x higher with a relatively faster f/8 system. The design turned out to be extremely difficult using only one diffractive surface. Even with many freeform optical elements, and putting a grating on a toroid surface, the image performance was still not satisfactory.

Posted in: Briefs, TSP, Imaging, Photonics, Mirrors, Optics, Spectroscopy, Optics, Spectroscopy, Product development
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Spinal Ultrasound Just-in-Time Training Tool

This software facilitates ultrasound imaging of the cervical and lumbar spine by crewmembers in-flight.

Lyndon B. Johnson Space Center, Houston, Texas

Back pain and injury are recognized risks that can affect the well-being and performance of crewmembers during missions, as well as their long-term health. Spine elongation is a documented effect of microgravity, back pain is a common occurrence in early flight, and the post-flight incidence of spinal injury is higher than the population average. These observations suggest that spinal unloading results in a transition to a new set point for the spine, and causes discomfort and an increased risk of injury.

Posted in: Briefs, TSP, Imaging, Photonics, Personnel, Injury causation, Spacecraft
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Wide-Spectrum Organic Mass Spectrometer Using Far-Ultraviolet Ionization

Lyndon B. Johnson Space Center, Houston, Texas

Two-step laser desorption/photoionization mass spectrometry (L2MS) represents a powerful tool for the organic analysis of astromaterials. The technique has high sensitivity and requires little to no sample preparation.

Posted in: Briefs, TSP, Imaging, Photonics, Lasers, Spectroscopy, Lasers, Spectroscopy, Particulate matter (PM), Test equipment and instrumentation
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