Tech Briefs

Domain-Engineered Magnesium-Oxide-Doped Lithium Niobate for Lidar-Based Remote Sensing

Current work provides a path to the development of compact, single-frequency, spectroscopically useful laser sources. Goddard Space Flight Center, Greenbelt, Maryland There are several frequency conversion applications associated with lidar-based remote sensing that would benefit from the use of high-quality, complex (i.e., chirped, multi-section, or otherwise modulated) domain-engineered magnesiumoxide- doped lithium niobate (MgO:LN). While congruently melting lithium niobate (CLN) has been explored in detail over the last decades, it is known to be highly susceptible to photorefractive damage, which has limited the achievable performance of some QPM-assisted (quasi phase matching) structures that are commercially available. The demand for high-performance engineered nonlinear optical (NLO) materials, in terms of power handling, efficiency, conversion bandwidth, and accessible wavelength range, has driven the development of high-quality, large-area wafers of MgO:LN. While commercial outlets for these materials exist, there is still a need to expand the achievable performance of these structures (i.e. larger aperture bulk structures, higher efficiency waveguide structures, and implementation of sophisticated poling designs that increase achievable conversion bandwidths).

Posted in: Briefs, Tech Briefs, Photonics

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Fiber-Optic Sensor for Aircraft and Structure Lightning Measurement

Langley Research Center, Hampton, Virginia An optical-fiber sensor based on Faraday Effect was developed for measuring total lightning current. Designed for aircraft installation, it is lightweight, non-conducting, structure conforming, and is immune to electromagnetic interference, hysteresis, and saturation. It can also be used on windmills, lightning towers, and can help validate lightning detection network measurements.

Posted in: Briefs, TSP, Tech Briefs, Photonics

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Generating Broadband Terahertz Radiation from Microplasma in Air

Researchers at the University of Rochester’s Institute of Optics have shown that a laser-generated microplasma in air can be used as a source of broadband terahertz radiation. Fabrizio Buccheri and Xi-Cheng Zhang recently demonstrated that an approach for generating terahertz waves using intense laser pulses in air – first pioneered in 1993 – can be done with much lower power lasers, a major challenge until now.

Posted in: Articles, Briefs

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Enhancing Neutron Imaging with Grazing Incidence Optics

Marshall Space Flight Center, Alabama A low-cost optical element was developed specifically for neutron optics applications. The technology operates as a reflective lens — similar to proven grazing incidence optics used for x-ray imaging — and improves neutron imaging resolution for applications using low-energy (<1 electron volt) neutrons.

Posted in: Briefs, Optics

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Free Space Optical Receiver for Data Detection and Radio Science Measurements

This technique is intended to save power, bandwidth, and scheduling demands on the spacecraft. NASA’s Jet Propulsion Laboratory, Pasadena, California For deep space communication systems, the decision of whether or not to suppress the transmitted carrier has always been an issue. For certain missions that use high data rates, the available bandwidth might be a limiting factor. In such cases, it is preferred to use a completely suppressed carrier system that is more bandwidth efficient.

Posted in: Briefs, TSP, Data Acquisition, Sensors

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Precision Miniature Attitude Determination and Control System

The system is designed to function with a high degree of autonomy. Goddard Space Flight Center, Greenbelt, Maryland The MAI-400SS Space Sextant is a turnkey Attitude Determination And Control System (ADACS) for CubeSats and nanosatellites. It is an enhanced version of the MAI-400, which is a precision CubeSat ADACS incorporating three reaction wheels, three electromagnets, and an ADACS computer in a ½-U module. This Space Sextant version incorporates two star trackers to improve overall pointing knowledge to 0.02° or better. The star trackers feature “Lost In Space” attitude determination requiring no a priori information.

Posted in: Briefs, TSP

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Combined Detection and Tracking of Moving Objects in Aerial Surveillance Images

NASA’s Jet Propulsion Laboratory, Pasadena, California This software implements a new probabilistic framework for integrated multi-target detection and tracking of small moving objects in image sequences, with specific application to tracking people in aerial images, in which image stabilization is inherently noisy.

Posted in: Briefs

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