Photonics

Electroform/Plasma-Spray Laminates for X-Ray Optics

Properties of lightweight components can be optimized. Goddard Space Flight Center, Greenbelt, Maryland Electroform/ plasma-spray laminates have shown promise as lightweight, strong, low-thermal-expansion components for x-ray optics. The basic idea is to exploit both (1) the well-established art of fabrication of optical components by replication and (2) plasma spraying as a means of reinforcing a thin replica optic with one or more backing layer(s) having tailorable thermomechanical properties. In x-ray optics as in other applications, replication reduces the time and cost of fabrication because grinding and polishing can be limited to a few thick masters, from which many lightweight replicas can thereafter be made.

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Preventing Raman Lasing in High-Q WGM Resonators

Raman-lasing threshold power is increased through suitable choice of dimensions. NASA’s Jet Propulsion Laboratory, Pasadena, California A generic design has been conceived to suppress the Raman effect in whispering-gallery-mode (WGM) optical resonators that have high values of the resonance quality factor (Q). Although it is possible to exploit the Raman effect (even striving to maximize the Raman gain to obtain Raman lasing), the present innovation is intended to satisfy a need that arises in applications in which the Raman effect inhibits the realization of the full potential of WGM resonators as frequency-selection components. Heretofore, in such applications, it has been necessary to operate high-Q WGM resonators at unattractively low power levels to prevent Raman lasing. (The Raman-lasing thresholds of WGM optical resonators are very low and are approximately proportional to Q–2.)

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Procedures for Tuning a Multiresonator Photonic Filter

A desired high-order filter function can be established and maintained. NASA’s Jet Propulsion Laboratory, Pasadena, California Two procedures have been devised for tuning a photonic filter that comprises multiple whispering-gallery-mode (WGM) disk resonators. As used here, “tuning” signifies locking the filter to a specific laser frequency and configuring the filter to obtain a desired high-order transfer function.

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Extended-Range Ultrarefractive 1D Photonic Crystal Prisms

Practical applications could include miniature spectrometers and wavelength-division multiplexers. NASA’s Jet Propulsion Laboratory, Pasadena, California A proposal has been made to exploit the special wavelength-dispersive characteristics of devices of the type described in “One-Dimensional Photonic Crystal Superprisms” (NPO-30232) NASA Tech Angle of Incidence Briefs, Vol. 29, No. 4 (April 2005), page 10a. A photonic crystal is an optical component that has a periodic structure comprising two dielectric materials with high dielectric contrast (e.g., a semiconductor and air), with geometrical feature sizes comparable to or smaller than light wavelengths of interest.

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Robust Mapping of Incoherent Fiber-Optic Bundles

Images scrambled by the bundles can be unscrambled. Marshall Space Flight Center, Alabama A method and apparatus for mapping between the positions of fibers at opposite ends of incoherent fiber-optic bundles have been invented to enable the use of such bundles to transmit images in visible or infrared light. The method is robust in the sense that it provides useful mapping even for a bundle that contains thousands of narrow, irregularly packed fibers, some of which may be defective.

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Compact, Stiff, Lightweight, Quick-Release Clamp

This clamp offers several advantages over a prior toggle-action clamp. The term "COSMOWRAP" denotes a compact, stiff, remotely actuatable, lightweight, quick-release clamp that could be substituted for the larger, heavier, and more-difficult-to-use toggle-action clamp now used in the space shuttle orbiter docking system (ODS) to perform contingency separations. In comparison with prior hand-operated devices designed for the same purpose, the COSMOWRAP is smaller and lighter in weight, yet offers greater capabilities. The COSMOWRAP (see figure) contains no spring and requires no pre-flight calibration or maintenance. The COSMOWRAP is expected to perform well, not only in the space-shuttle application for which it was originally designed, but also in terrestrial applications. Because the design of the COSMOWRAP reduces the force needed for installation or removal and provides for release by the action of one hand, the replacement of the ODS toggle-action clamp by the COSMOWRAP can be expected to contribute to crew safety in the United States space program and on the International Space Station.

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Video-Based Foreign Object Detection

The technique can be applied to any assembly process where inclusion of foreign material can cause harm. The Boeing Company has developed an overhead camera system that can automatically spot small pieces of debris on a work surface that might otherwise go unnoticed. The system automatically analyzes inputs from one or more video cameras to detect undesirable colors representing materials that, if left in place, would degrade part quality. The system uses commercial off-the-shelf hardware and software for low-cost implementation and is currently in use in the Boeing F/A-18 wing production line (see figure). The patent-pending technology, known as foreign-object video detection and alert system and method, is available for license.

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