Diode-pumped nonresonant continuous-wave Raman laser in H_2 with resonant optical feedback stabilization

We demonstrate a nonresonant cw Raman laser pumped by an optically locked diode laser at 790 nm that produces cw Stokes (1178-nm) and coherent anti-Stokes (595-nm) emission. Considering the modest pump powers, relative low cost, and predicted spectral purity, we expect that frequency downconversion of tunable diode lasers through stimulated Raman scattering will provide an attractive source for remote sensing, spectroscopic, and atomic physics applications. The Stokes laser threshold is $240\pm 19 \mathit{\mu }\mathrm{W}$ pump power, and emission is observed over a roughly 10-nm range by adjustment of the optical locking feedback phase. Photon-conversion efficiency rises throughout the pump-power region, with a peak value of $15\pm 2\%$.