Greater Than 90% Conversion Efficiency By Stimulated Rotational Raman Scattering In Hydrogen (H2)

Stimulated rotational Raman scattering (SRRS) has been used with a variety of pump lasers and Raman media to shift to longer wavelengths. In 1989 we reported on the efficient generation of SRRS in hydrogen using a phase conjugate, frequency doubled Nd:YAG laser. We achieved a maximum SRRS conversion of 88% with the energy concentrated in the first three rotational Stokes lines. These results were obtained with a single focus geometry. A two cell dual focus configuration was reported later in 1989 by S.R. Bowman, et al, with enhanced rotational Raman conversion into the first rotational line.