Investigations for phase conjugation by stimulated Brillouin scattering of pulsed high-energy CO2 laser radiation

摘要

Abstract: uirements for obtaining phase conjugation due to stimulated Brillouin-scattering of CO$-2$/-laser radiation in high pressure gases have been investigated. The steady state gain factors and the phonon lifetimes for different gases at 10.6 $mu@m were calculated. Simply focussing a pulsed TEA-CO$-2$/ laser beam up to power densities near below the gas breakdown threshold proved not to be sufficient for initiating the stimulated Brillouin scattering process. With a special oscillator amplifier setup and feedback system it was possible, however, to overcome these constraints so that for the first time measurements of stimulated CO$-2$/-radiation back-scattering in various gases can be reported. !20