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Accession Number:
AD0816417
Title:
HIGH INTENSITY LASER PROPAGATION IN THE ATMOSPHERE
Descriptive Note:
Final rept. 1 Nov 1965-28 Feb 1967
Corporate Author:
TRW SYSTEMS REDONDO BEACH CA QUANTUM PHYSICS LAB
Report Date:
1967-02-28
Pagination or Media Count:
117.0
Abstract:
The phenomena which constitute ultimate limitations to the transmission of intense laser radiation through the atmosphere are investigated, namely, self-defocusing due to atmospheric heating and the stimulated Raman effect. The heating studies are concerned with processes contributing to residual absorption in atmospheric transmission windows. A quantum mechanical study of the far-wing pressure broadening of molecular vibrational lines is carried out. The spectral distance beyond which the Lorentz-type behavior fails is found as a function of temperature and range of the interaction potential. It is shown that far wing fall-off is exponential. An analysis is made of collision induced absorption with emphasis on the far-wing behavior. A calculation is performed specifically for absorption during collisions between rare gas atoms a numerical computation phase remains. Laser beam depletion by stimulated Raman scattering is investigated using a rate equation description. The particular effects are the interaction of competing Raman backscattered light, and the effect of pressure dependence on the propagation of a beam vertically through the atmosphere. The maximum intensity which can be transmitted through the atmosphere without frequency change due to Raman scattering is calculated.
Distribution Statement:
APPROVED FOR PUBLIC RELEASE
