Briefs: Photonics/Optics
Three-Color Focal-Plane Array of Infrared QWIPs
A proposed focal-plane array (FPA) of quantum-well infrared photodetectors (QWIPs) would sense images in three different infrared wavelength bands simultaneously. These and other QWIP infrared...
Briefs: Photonics/Optics
Update on Fuzzy-Logic-Enhanced Digital-PIV Software
Two reports present additional information on the subject matter of "Software for Processing Data in Particle-Image Velocimetry" (LEW-16857),NASA Tech Briefs, Vol. 24, No. 1 (January 2000), page 26a. Like the cited prior article, both reports discuss the principles and the practical aspects of...
Briefs: Photonics/Optics
Two-Color Random Reflectors for QWIPs
Random reflectors of a proposed type would be fabricated on the back surfaces of quantum-well infrared photodetectors (QWIPs) to increase the coupling efficiency of infrared light into the QWIPs in two...
Briefs: Photonics/Optics
Tridirectional Gratings as Improved Couplers for QWIPs
Tridirectional diffraction gratings have been proposed to provide optical coupling to quantum-well infrared photodetectors (QWIPs) in focal-plane arrays. The tridirectional gratings...
Briefs: Photonics/Optics
Optical Filters Based on Dense Arrays of Microscopic Pillars
A proposal for development of a class of high-transmission and antireflection optical filters is derived from the observation that the eyes of moths reflect almost no light, regardless of the wavelength or the angle of incidence of illumination. The low-reflection property of moth...
Briefs: Photonics/Optics
Organic Light-Emitting Diodes (OLED) Have Many Potential Uses
Organic light-emitting diodes (OLEDs) are grounded in a self-luminous display technology based on thin organic films as the light emitter. Like conventional inorganic...
Briefs: Photonics/Optics
Simplified Radiometer for Quantifying Aircraft Icing Hazard
A simplified microwave radiometric apparatus has been proposed for use in quantifying the potential danger of accretion of ice onto an aircraft flying through a cloud. The quantity...
Briefs: Photonics/Optics
Development of Multimode-Optical-Fiber Imaging Probe
A developmental electro-optical system would enable remote real-time viewing of a scene through a multimode optical fiber, as though the fiber were a conventional image-transmitting optic...
Briefs: Manufacturing & Prototyping
Fabricating Small Apertures in Silicon-on-Insulator Wafers
Precise small apertures for a variety of optical applications can be formed in silicon-on-insulator (SOI) wafers by use of a photolithographic process developed specifically for the...
Briefs: Photonics/Optics
Cancellation of Laser Noise in an Unequal-Arm Interferometer
A method of processing phase measurements in an unequal-arm laser Michelson interferometer makes it possible to detect phase effects much smaller than the laser phase noise. In...
Briefs: Photonics/Optics
Tunable, Single-Frequency, Fiber Fabry-Perot VCSELs
The figure depicts several aspects of a unique type of vertical-cavity surface-emitting lasers (VCSELs) that incorporate fiber Fabry-Perot (FFP) optical cavities. These lasers have been...
Briefs: Photonics/Optics
Reducing the Volume of a Holographic Data-Storage System
The size of a holographic data-storage system could be reduced by a proposed design modification that calls for replacement and repositioning of some optical components and the use of...
Briefs: Photonics/Optics
Filterless Si-Based Ultraviolet-Selective Photodetectors
Monolithic semiconductor photodiodes that discriminate against infrared and visible light and that can be tailored to detect ultraviolet light in selected wavelength bands have been...
Briefs: Photonics/Optics
Generating Synchronized WDM Pulses in a Nonlinear Optical Fiber
Pulse shepherding (defined below) can be exploited to impress synchronized amplitude-modulation pulses, with durations of the order of picoseconds, onto beams of light with...
Briefs: Photonics/Optics
Improved Cross-Correlation Dynamic-Light-Scattering Method
A dynamic-light-scattering (DLS) method that reduces undesired contributions from multiply scattered photons has been invented. The method involves, among other things,...
Briefs: Photonics/Optics
Alloy Casting Produces New Mirror Technology
Under a Phase 1 Small Business Technology Transfer (STTR) award of $99,000 with Goddard Space Flight Center, Advanced Optical Systems Inc. (AOS) has produced a 13.5-kg/m2 6-in.-diameter...
Briefs: Photonics/Optics
Lightweight Reflector Dishes Would Be Made by Spin Casting
Lightweight reflector dishes for radio antennas would be mass-produced cheaply by spin casting of polymers, according to a proposal. These reflector dishes were conceived for compact stowage followed by deployment and operation aboard spacecraft, but might also be useful on Earth in...
Briefs: Photonics/Optics
Retroreflective Communication Systems
A retroreflective communication system (RCS), is a state-of-the-art system that provides (1) two-way optical communication using only one transmitter and (2) multipath communication among remote locations. RCSs were conceived for use in communication among stations on the ground and aboard spacecraft in...
Briefs: Electronics & Computers
Low-Sidelobe Phased-Array-Fed Cylindrical-Reflector Antenna
A phased-array-fed cylindrical-reflector antenna with superquadric projected aperture has been designed to afford the ability to scan the beam over a wide angular range without...
Briefs: Electronics & Computers
SiC-Based Black-Body Absorbers for Submillimeter Wavelengths
Open-cell silicon carbide foam coated with a ferrite-filled absorbing resin has been found to be useful for black-body absorbers at millimeter and submillimeter wavelengths. The...
Briefs: Photonics/Optics
Adaptive Filtering of SAR Interferograms
An algorithm for filtering synthetic-aperture-radar (SAR) interferograms has been developed which substantially improves the performance of subsequent phase-unwrapping. It accomplishes this task by filtering the interferogram strongly in areas where the scene contains little detail, and weakly where the...
Briefs: Photonics/Optics
Software for Processing Data in Particle-Image Velocimetry
PIVPROC is a computer program for processing data in particle-image velocimetry (PIV), which is a method of determining a flow velocity field from images of small seed particles that are entrained in the flow and that are illuminated by laser pulses at known intervals of time. PIVPROC...
Briefs: Photonics/Optics
Current-Mode Dark-Level Subtraction in LWIR Imaging
A complementary metal oxide/semiconductor (CMOS) focal-plane readout circuit for an imaging array of long-wavelength infrared (LWIR) photodetectors effects in-pixel current-mode...
Briefs: Photonics/Optics
High-Power, Wideband Laser-Diode Transmitter Module
A prototype compact, rugged optomechanical module contains a high-power, wideband laser-diode transmitter. The laser diode is of a commercial single-quantum-well AlGaAs type. Each laser diode of this type is manufactured for a specific nominal wavelength in the range from 810 to 860 nm; the...
Briefs: Photonics/Optics
Segmented-Cold-Cathode Display Panels
Display panels based largely on the principles of proximity-focused image-intensifier tubes have been proposed as alternatives to cathode-ray tubes (CRTs) and other conventional devices for wide...
Briefs: Photonics/Optics
Method of Measuring Encircled Energy for Imaging Optics
The radial distribution of energy within an image, called encircled energy, is a classical measure of the quality of the optical system producing that image. An improved method for measuring encircled or enclosed energy for imaging optical systems makes use of precisely micromachined...
Briefs: Photonics/Optics
Telescope for Imaging and Laser Communication
Miniature, single-aperture optoelectronic instruments called "multi-function telescopes" are being developed for use in both scientific observations and laser communications aboard...
Briefs: Photonics/Optics
Multiple Scattering Suppression in Laser Light Scattering
A laser-light-scattering method that includes cross-correlation processing of photodetector output signals has been devised for use in measuring the Brownian motions, and thereby...
Briefs: Photonics/Optics
Robot Would Inspect Hanging Cables
A proposed automated apparatus would travel along a hanging cable, optically inspecting it all around. The proposal was made to eliminate lowering human inspectors in baskets along emergency-egress slidewires at Kennedy Space Center launch pads. The apparatus would include a motor drive system, a video camera...
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