Photonics/​Optics

Access our comprehensive library of technical briefs on photonics and optics, from engineering experts at NASA and major government, university, and commercial laboratories.

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Briefs: Photonics/Optics
Spurious interference limits the performance of many interferometric measurements. Digitally enhanced interferometry (DEI) improves measurement sensitivity by augmenting conventional heterodyne...
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Briefs: Photonics/Optics
Multiparallel Three-Dimensional Optical Microscopy
Multiparallel three-dimensional optical microscopy is a method of forming an approximate three-dimensional image of a microscope sample as a collection of images from different depths through the sample. The imaging apparatus includes a single microscope plus an assembly of beam splitters and...
Briefs: Photonics/Optics
Sub-aperture interferometers — also called wavefront-split interferometers — have been developed for simultaneously measuring displacements of multiple targets. The terms “sub-aperture” and...
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Briefs: Physical Sciences
Vacuum-Compatible Wideband White Light and Laser Combiner Source System
For the Space Interferometry Mission (SIM) Spectrum Calibration Development Unit (SCDU) testbed, wideband white light is used to simulate starlight. The white light source mount requires extremely stable pointing accuracy ( lights were coupled to a photonic crystal fiber (PCF).
Briefs: Photonics/Optics
In the process of connecting widely distributed antennas into a coherent array, it is necessary to synchronize the timing of signals at the various locations. This can...
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Briefs: Photonics/Optics
Optical Tapers as White-Light WGM Resonators
A theoretical analysis has revealed that tapered optical waveguides could be useful as white-light whispering-gallerymode (WGM) optical resonators. The compactness and the fixed-narrow-frequency- band nature of the resonances of prior microdisk and microsphere WGM resonators are advantageous in...
Briefs: Photonics/Optics
Solar Rejection Filter for Large Telescopes
To reject solar radiation photons at the front aperture for large telescopes, a mosaic of large transmission mode filters is placed in front of the telescope or at the aperture of the dome. Filtering options for effective rejection of sunlight include a smaller filter down-path near the focus of the...
Briefs: Photonics/Optics
Free-Space Optical Interconnect Employing VCSEL Diodes
Sensor signal processing is widely used on aircraft and spacecraft. The scheme employs multiple input/output nodes for data acquisition and CPU (central processing unit) nodes for data processing. To connect 110 nodes and CPU nodes, scalable interconnections such as backplanes are desired...
Briefs: Photonics/Optics
Two recipes for ensuring critical coupling between a single-mode optical fiber and a whispering-gallery-mode (WGM) optical resonator have been devised. The recipes provide for phase...
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Briefs: Manufacturing & Prototyping
Mercuric Iodide Anticoincidence Shield for Gamma-Ray Spectrometer
A film-growth process was developed for polycrystalline mercuric iodide that creates cost-effective, large-area detectors for high-energy charged-particle detection. A material, called a barrier film, is introduced onto the substrate before the normal mercuric iodide film growth...
Briefs: Photonics/Optics
Rectangular-waveguide inserts that are made of non-ferromagnetic metals and are sized and shaped to function as notch filters have been conceived as reference standards for use in the...
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Briefs: Physical Sciences
The acronym “CHAMP” (signifying “camera, hand lens, and microscope”) denotes any of several proposed optoelectronic instruments that would be capable of color imaging at working distances that...
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Briefs: Physical Sciences
Lightweight cylindrical reflectors of a proposed type would be made from reflective membranes stretched between pairs of identically curved and identically oriented end rails. In each such...
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Briefs: Semiconductors & ICs
Silicon Wafer-Scale Substrate for Microshutters and Detector Arrays
The silicon substrate carrier was created so that a large-area array (in this case 62,000+ elements of a microshutter array) and a variety of discrete passive and active devices could be mounted on a single board, similar to a printed circuit board. However, the density and...
Briefs: Physical Sciences
Integrated miniature planar arrays of optical sensors for detecting specific biochemicals in extremely small quantities have been proposed. An array of this type would have an area of...
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Briefs: Electronics & Computers
Inter-Symbol Guard Time for Synchronizing Optical PPM
An inter-symbol guard time has been proposed as a means of synchronizing the symbol and slot clocks of an optical pulse-position modulation (PPM) receiver with the symbol and slot periods of an incoming optical PPM signal. (Such synchronization is necessary for correct identification of received...
Briefs: Photonics/Optics
The figure schematically depicts some alternative designs of proposed compact, lightweight optoelectronic microscopes that would contain no lenses and would generate magnified video images of...
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Briefs: Physical Sciences
An analog electronic camera that is part of a metrology system measures the varying direction to a light-emitting diode that serves as a bright point target. In the original application for which...
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Briefs: Physical Sciences
The figure depicts a proposed wide-angle lens that would be especially well suited for an electronic camera in which the focal plane is occupied by an image sensor that has small...
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Briefs: Photonics/Optics
A method of polarimetric imaging, now undergoing development, involves the use of two photoelastic modulators in series, driven at equal amplitude but at different frequencies. The net...
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Briefs: Photonics/Optics
Modal Filters for Infrared Interferometry
Modal filters in the ≈10-μm spectral range have been implemented as planar dielectric waveguides in infrared interferometric applications such as searching for Earth-like planets. When looking for a small, dim object (“Earth”) in close proximity to a large, bright object (“Sun”), the...
Briefs: Imaging
An established method of room-temperature interferometric null testing of mirrors having simple shapes (e.g., flat, spherical, or spheroidal) has been augmented to enable measurement of...
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Briefs: Photonics/Optics
A proposed metrology system would be incorporated into a proposed telescope that would include focusing optics on a rigid bench connected via a deployable mast to another rigid bench...
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Briefs: Photonics/Optics
Formation Flying of Components of a Large Space Telescope
A conceptual space telescope having an aperture tens of meters wide and a focal length of hundreds of meters would be implemented as a group of six separate optical modules flying in formation: a primary-membrane-mirror module, a relay-mirror module, a focal-plane-assembly module containing...
Briefs: Photonics/Optics
Laser Metrology Heterodyne Phase-Locked Loop
A method reduces sensitivity to noise in a signal from a laser heterodyne interferometer. The phase-locked loop (PLL) removes glitches that occur in a zero-crossing detector's output [that can happen if the signal-to-noise ratio (SNR) of the heterodyne signal is low] by the use of an internal oscillator...
Briefs: Electronics & Computers
Crystalline whispering gallery mode resonators (CWGMRs) made of crystals with axial symmetry have ordinary and extraordinary families of optical modes. These modes have substantially...
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Briefs: Electronics & Computers
Spatial Modulation Improves Performance in CTIS
Suitably formulated spatial modulation of a scene imaged by a computed-tomography imaging spectrometer (CTIS) has been found to be useful as a means of improving the imaging performance of the CTIS. As used here, “spatial modulation” signifies the imposition of additional, artificial structure on...
Briefs: Photonics/Optics
Phase matching of diverse electromagnetic modes (specifically, coexisting optical and microwave modes) in a whispering-gallery-mode (WGM) resonator has been predicted theoretically and verified...
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Briefs: Photonics/Optics
Microwave-to-optical frequency converters based on whispering-gallery-mode (WGM) resonators have been proposed as mixers for the input ends of microwave receivers in which, downstream of the...
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