Laser-induced damage threshold of the nonlinear crystals BaGa₄Se₇ and BaGa₂GeSe₆ at 2091 nm in the nanosecond regime

The surface laser-induced damage threshold (LIDT) of BaGa4Se7 and BaGa2GeSe6 nonlinear crystals was studied at 2091 nm. Both yellow and dark yellow phases of BaGa4Se7 were investigated. The Ho:YAG laser generating nanosecond pulses at 2 kHz, 5 kHz, and 10 kHz was used as a radiation source. The R-on-1 procedure was applied to determine the 0% probability damage threshold. The LIDT of the dark yellow phase of BaGa4Se7 without cleavage planes is very close to the BaGa2GeSe6 LIDT and exceeds by ca. 30% the LIDT of the yellow phase of BaGa4Se7 at 2 and 5 kHz.