Optical Damage Threshold of BaGa2GeS6 Crystals Irradiated with 1.03 μm Femtosecond and Picosecond Laser Pulses

Abstract

We report the experimental measurement of the optical damage threshold of the BaGa₂GeS₆ crystal surface irradiated with laser pulses with a wavelength of 1.03 μm and pulse durations ranging from 0.3 to 10 ps. Under single-pulse irradiation, the threshold energy density for optical damage was approximately 0.6 J/cm² (intensity ∼1.8 TW/cm²) for 0.3 ps pulses and increased gradually to 2.2 J/cm² (intensity ∼0.22 TW/cm²) for 10 ps pulses. The optical damage threshold of the BaGa₂GeS₆ crystal surface is found to exhibit a weak dependence on the pulse repetition rate: as the frequency increases from 1 Hz to 100 kHz, the optical damage threshold decreases from 0.6 to 0.45 J/cm². Analysis of literature data shows that the optical damage threshold for BaGa₂GeS₆ irradiated by femto- and picosecond laser pulses with a wavelength of 1 μm is an order of magnitude higher than that of traditional nonlinear crystals such as AgGaS₂ and LiGaS₂.