Output performance of a liquid-N2-cooled, para-H2 Raman laser

Abstract

Stimulated rotational Raman scattering (SRRS) of a transversely excited atmosphere‐CO₂ laser in para‐H₂ was studied with a liquid‐N₂‐cooled multiple‐pass cell. Line‐tunable output from 13.7 to 17.2 μm was obtained by changing CO₂ pump lines. Threshold pump energies required for SRRS were measured to be 0.9 and 1.5 J for the 9P(20) and 10P(20) CO₂ lines, respectively. Above the threshold, the Stokes output energies for the 10‐μm band pumping increased in proportion to the increase of the pump energies, while the increase of the Stokes output for the 9‐μm band pumping was limited. Para‐H₂ pressure dependence of the Stokes output energy showed that the Stokes gain became constant for pressures above 250 Torr at 100 K.