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Proceedings Paper

An Infrared Radiation Detector For Laser Diagnostics
Author(s): J. E. Thompson
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Paper Abstract

A liquid biased, liquid crystal, infrared radiation detector has been devised for the purpose of determining the time integrated output spectrum and power spatial distribution of infrared radiation. The device has been specifically used to measure the spectrum and spaital power distribution of the output of a quasi-cw carbon monoxide gas laser. The detector recording medium is composed of thin mylar coated with temperature sensitive, encapsulated, cholesteric, liquid crystals and energy absorbing black paint. A uniform spatial color distribution of the liquid crystals is established and maintained by immersion in a controlled temperature liquid bath. The resulting uniform color distribution is modified, at various spatial points, by the addition of laser energy obtained either indirectly from the laser output coupler to yield the spatial dependence of the near or far field laser output or from a spectrometer output to yield the spectrum of the laser output. The addition of less than 15 mJ/cm2 of incident energy is adequate to modify the color distribution. The uniformity and precise control of the liquid crystal temperature and hence color, by the use of a liquid bath, makes it possible to compare colors, and hence laser output powers, at various spatial points. This permits the mapping of the laser near field output spatial distribution and the distribution of the laser spectrum with greater sensitivity than has been possible with more conventional tech, niques. Results showing the near field energy distribution and output spectrum of a supersonic flow, electric discharge CO laser obtained using the detection technique will be presented.

Paper Details

Date Published: 24 November 1975
PDF: 6 pages
Proc. SPIE 0069, Optical Design Problems in Laser Systems, (24 November 1975); doi: 10.1117/12.954561
Show Author Affiliations
J. E. Thompson, Northrop Research and Technology Center (United States)

Published in SPIE Proceedings Vol. 0069:
Optical Design Problems in Laser Systems
Walter R. Sooy, Editor(s)

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