Laser damage studies of CdSiP2 and ZnGeP2 nonlinear crystals with nanosecond pulses at 1064 and 2090 nm

CdSiP 2 (CSP) is a very promising nonlinear crystal for the mid-IR spectral range with a nonlinear coefficient slightly larger than that of ZnGeP2 (ZGP). In contrast to ZGP, CSP is phase-matchable and can be employed in 1.064-μm pumped optical parametric oscillators (OPOs) without two-photon absorption. Although low damage resistivity has been reported in such initial OPO tests of CSP, no reliable data on the damage-threshold of uncoated CSP exists. We compare in this work the damage resistivity of uncoated CSP with ZGP at two wavelengths, 2.09 μm (1 kHz, 21 ns) and 1.064 μm (100 Hz, 8 ns).