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Micron-Accurate Laser Fresnel-Diffraction Ranging System

This system would exploit the variation of Fresnel diffraction with distance. Marshall Space Flight Center, Alabama The figure schematically depicts two versions of an opto-electronic system, undergoing development at the time of reporting the information for this article, that is expected to be capable of measuring a distance between 2 and 10 m with an error of no more than 1 μm. The system would be designed to exploit Fresnel diffraction of a laser beam. In particular, it would be designed to take advantage of the fact that a Fresnel diffraction pattern is ultrasensitive to distance.

Posted in: Tech Briefs, ptb catchall, Photonics, Briefs

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Spatial Combining of Laser-Diode Beams for Pumping an NPRO

Multiple multimode beams are efficiently combined into one optical fiber. NASA’s Jet Propulsion Laboratory, Pasadena, California A free-space optical beam combiner now undergoing development makes it possible to use the outputs of multiple multimode laser diodes to pump a neodymium-doped yttrium aluminum garnet (Nd:YAG) non-planar ring oscillator (NPRO) laser while ensuring that the laser operates at only a single desired frequency. This optical beam combiner serves the same purpose as does the one described in “Diffractive Combiner of Single-Mode Pump Laser-Diode Beams” (NPO-42411), NASA Tech Briefs, Vol. 31, No. 5 (May 2007), page 16a. Although the principles of design and operation of the present and prior beam combiners are not identical, they are so closely related that it is necessary to devote the next four paragraphs to reiteration of a substantial portion of the cited prior article in order to give meaning to a description of the present beam combiner.

Posted in: Tech Briefs, ptb catchall, Photonics, Briefs

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Polarization/Spatial Combining of Laser-Diode Pump Beams

Four beams are combined into two, which are then combined into one. NASA’s Jet Propulsion Laboratory, Pasadena, California The figure depicts a breadboard version of an optical beam combiner that makes it possible to use the outputs of any or all of four multimode laser diodes to pump a non-planar ring oscillator (NPRO) laser. This apparatus could be an alternative to the one described in the immediately preceding article. Whereas that one utilizes spatial (beam-shaping) beam-combining techniques, this one utilizes a combination of polarization and spatial beam-combining techniques. In both that case and this one, the combined multiple laser-diode pump beams are coupled into an optical fiber for delivery to the NPRO pump optics.

Posted in: Tech Briefs, ptb catchall, Photonics, Briefs

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Web-Enabled Optoelectronic Particle-Fallout Monitor

A user can interrogate this instrument from a remote location. John F. Kennedy Space Center, Florida A Web-enabled optoelectronic particle-fallout monitor has been developed as a prototype of future such instruments that (l) would be installed in multiple locations for which assurance of cleanliness is required and (2) could be interrogated and controlled in nearly real time by multiple remote users. Like prior particle-fallout monitors, this instrument provides a measure of particles that accumulate on a surface as an indication of the quantity of airborne particulate contaminants. The design of this instrument reflects requirements to:

Posted in: Tech Briefs, ptb catchall, Photonics, Briefs

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Photonics West Exhibitor Preview

View these and other new products on display by exhibitors at Photonics West, January 22-24, in San Jose, CA. Visit Photonics Tech Briefs at Booth 1437.Visit http://spie.org/x2584.xml for more information.

Posted in: Products

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Hybrid Modeling Improves Health and Performance Monitoring

Scientists and engineers have long used computers to model physical systems. Physical modeling is a major part of design and development processes, as well as failure analysis. At NASA, scientists and engineers rely heavily on physical modeling to evaluate the overall health and performance of all mission-related flight vehicles.

Posted in: NTB, Spinoff

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Design Application Translates 2-D Graphics to 3-D Surfaces

When it comes to solving some of NASA’s most challenging technical problems, the mathematical minds that make up the Computational Sciences Branch at NASA’s Glenn Research Center are ready and waiting to crunch some numbers. Calculating complex algorithms and mathematical equations like it’s child’s play, the group has worked out many technical issues for NASA over the years.

Posted in: NTB, Spinoff

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