Stimulated rotational Raman scattering in CO2-pumped para-H2

Stimulated rotational Raman scattering in a 300 K multipass cell filled with para-H
2
with a single-mode CO
2
pump laser was studied using a single-mode OPO as a probe laser at the Stokes frequency for the S
o
(0) transition. Amplification and pump depletion are examined as a function of incident pump energy. For an incident CO
2
pump laser energy of 1.5 J, a photon conversion efficiency of 47 percent is observed.