Development of the 2.8 mu m emission doubly shifted Raman laser using stimulated Brillouin scattering in a cascaded cavity

Abstract

A doubly shifted Raman laser using CH4 gas has been developed for 2.8 mu m generation, pumped by a Nd: YAG laser with 65.5 mJ at 17 ns. A dichroically coated meniscus-type lens is modified to utilize the backward stimulated Brillouin scattering and backward Stokes beams from a previous laser design [Appl. Opt. 46,5516-5521 (2007)]. A maximum output energy of 4.76 mJ at 2.80 mu m wavelength has been achieved in the cascaded resonator. A maximum conversion efficiency of 8.9% has been achieved at a CH4 gas pressure of 600 psi. The obtained spatial beam profile is quite smooth, and its output pulse width is 10 ns. (C) 2008 Optical Society of America.