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Proceedings Paper

Slow-motion acquisition of laser beam profiles after propagation through gun blast
Author(s): Armin V. Kay
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Paper Abstract

Degradation of laser beam quality by special effects is considered to be of increasing importance for investigations concerning combat field communications. An 8-bit transient memory device has been developed which allows storing of a series of up to 15 laser beam intensity profiles using a CCD linear array of 1754 diodes with a spatial resolution of 10 micrometers . The shortest time interval between consecutive profiles amounts to 2 ms. Data reduction of the measured profiles can be achieved by best fit of a Gaussian normal distribution with four parameters representing bias level, peak amplitude, width (FWHM), and peak position. This procedure was applied to helium-neon-laser radiation after transmission through the gas blast expanding from a powder gun. Two different experimental arrangements have been realized so far. The first one comprises a large vessel which limits the expansion of the combustion products from a 20 mm-bore gun, and the laser beam traverses the barrel axis in front of the muzzle. The second set-up allows free gas blast expansion from a 40 mm-bore gun, the laser beam being adjusted parallel to the barrel axis. For both cases, the time behavior of beam extinction, broadening and wandering is reported. Absorption and scattering of radiation by shock waves, turbulent structures and aerosols in the exhaust cause considerable temporary alterations: peak intensity attenuation down to 0.1 beam width reaching up to twice its initial value, and beam deflection up to 2 mrad.

Paper Details

Date Published: 1 July 1991
PDF: 9 pages
Proc. SPIE 1486, Characterization, Propagation, and Simulation of Sources and Backgrounds, (1 July 1991); doi: 10.1117/12.45747
Show Author Affiliations
Armin V. Kay, French-German Research Institute of Saint-Louis (France)

Published in SPIE Proceedings Vol. 1486:
Characterization, Propagation, and Simulation of Sources and Backgrounds
Wendell R. Watkins; Dieter Clement, Editor(s)

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