DTIC ADA213926: Aspects of Raman Scattering | |
by Defense Technical Information Center | |
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Aspects of stimulated Raman scattering are investigated | |
to better understand the propagation of intense light | |
beams through the atmosphere. In addition, a new unstable | |
resonator cavities was developed for the long pulse | |
excimer laser used in the Raman beam-cleanup experiments | |
and have made preliminary measurements on an anti-Stokes | |
Raman laser which operates in the vacuum ultra violet | |
region of the spectrum. Experiments demonstrate the Raman | |
gain suppression observed on-axis, or at very small | |
angles, for rotational Raman gain using linearly | |
polarized beams in hydrogen and deuterium. The reduction | |
in vibrational Raman gain at the phase matching angle is | |
noted in hydrogen and deuterium. The normal exponential | |
gain observed in the transient limit has been modeled to | |
fit our experiment. The theory had to take account of the | |
actual beam shapes, both spatially and temporally, as | |
well as the self-phase modulation, in order to correctly | |
predict the observed gain functions. Experiments were | |
made on the beam quality and gain dependence of the 2nd | |
Stokes. In particular, a study of the seeding mechanism | |
responsible for generating the 2nd Stokes through the | |
threshold level, has required statistical, spectral, beam | |
profile and gain parameter studies. The far field pattern | |
was then compared with the Fourier transform of the near | |
field pattern to give a measure of the beam quality. | |
Pulse energy statistics of the self-generated Stokes as | |
well as of amplified and saturated Stokes have been | |
studied from the point of view of Raman beam control. | |
Such studies have mainly been restricted to Fresnel | |
number 1 systems although larger Fresnel number 10 | |
systems have been studied by the control exerted over the | |
spatial patterns. | |
Date Published: 2018-02-23 15:18:15 | |
Identifier: DTIC_ADA213926 | |
Item Size: 43887934 | |
Language: english | |
Media Type: texts | |
# Topics | |
DTIC Archive; Mahon, Rita; JAYCOR VIE... | |
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