Comparison of 1.15 µm Nd:YAG\KTA Raman lasers with 234 and 671 cm-1 shifts.

ABSTRACT

NdYAG/KTA intra-cavity Raman lasers with two different Raman shifts are experimentally compared for eradiating around 1.15 µm. The different Raman processes are attributed to polarization dependent Raman gain of KTA crystal and nearly linear polarization of NdYAG fundamental light with Q-switch operation. Under an incident pump power of 10.2 W and a pulse repetition frequency of 15 kHz, 1.24 W output for the third-Stokes at 1150 nm in X(ZZ)X Raman configuration with the Raman shifts of 234 cm-1 and 1.21 W output for the first-Stokes at 1146 nm in X(YY)X Raman configuration with the Raman shifts of 671 cm-1were achieved by rotating the KTA crystal. The conversion efficiency in both Raman configurations were about 12% respect to the same incident pump power. The slight differences of spectra and pulses are investigated.