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Proceedings Paper

Cylindrical light pipes for collecting light scattered from a Gaussian beam
Author(s): George W. Hopkins; Tad D. Simons
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Paper Abstract

An investigation to enhance the efficiency of Raman- scattered light showed that cylindrical light pipes can significantly increase light collection from a Gaussian beam. Further, the enhanced signal from the light pipe retains the image of the laser beam, permitting the use of smaller detectors and resulting in a favorable signal-to- noise ratios. This investigation focussed on real-time measurements of gaseous media in a laser buildup cavity; however, the imaging properties of the light pipe apply to all measurements of molecular scattering. The light pipe matched the constraints of our measurement system: spectral separation and detection with an optical spectrograph, the need to reduce background light, the need to minimize cost, and stimulation by a laser beam in an optical cavity. After initial experiments collecting light from the ends of light pipes, we developed light pipes with a window on the cylindrical surface. Light emitted from these windows is much more intense than the direct image of the laser beam (typically 10X for light pipes 50 - 100 mm long), and the signal retains the image of the beam. Computer ray tracing modeled this side collection using Monte Carlo techniques, which are discussed in detail. We fabricated and tested light pipes using several different coatings.

Paper Details

Date Published: 6 October 1999
PDF: 7 pages
Proc. SPIE 3781, Nonimaging Optics: Maximum Efficiency Light Transfer V, (6 October 1999); doi: 10.1117/12.368253
Show Author Affiliations
George W. Hopkins, Hewlett-Packard Co. (United States)
Tad D. Simons, Hewlett-Packard Co. (United States)

Published in SPIE Proceedings Vol. 3781:
Nonimaging Optics: Maximum Efficiency Light Transfer V
Roland Winston, Editor(s)

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