Abstract
Various aspects of stimulated rotational Raman scattering of a TEA-CO2 laser in para-H2 are studied with a liquid-N2 cooled multiple-pass cell. Line-tunable output from 13 to 30 μm is obtained by generating the 1st and 2nd Stokes waves. The 1st Stokes output energies for the 10 μm band pumping increase in proportion to the increase of the pump energies and the maximum conversion efficiency reaches 80%. On the other hand, the increase of the lst Stokes output for the 9 μm band pumping is limited because of generation of the 2nd Stokes wave. Beam crossing effect which is an important factor for achievement of high conversion efficiency in a multiple pass cell is analysed by numerical simulation. In addition, efficient conversion with the use of roomtemperature H2 is realised by improving optical condition.
