A kilohertz repetition rate 1.9 mu m H/sub 2/ Raman oscillator

Raman conversion of a high-repetition-rate Q-switched Nd:YAG laser using a gaseous H/sub 2/ Raman medium is reported. With a H/sub 2/ cell placed in a focusing intracavity Raman oscillator, 3 W of average power at 1.9 mu m was obtained from a 15-W 1.06- mu m laser operating at 2 kHz. Although the pump beam was multimode, the Stokes output was diffraction limited. At kilohertz repetition rates, conversion efficiencies were improved with a flowing gas cell which substantially reduced the thermal lensing effect in the Raman medium. A rate equation approach was used to model the intracavity conversion process.>