Radiation resistance of nonlinear crystals at a wavelength of 9.55 μm

The results of radiation resistance measurements for twelve nonlinear crystals are presented. The crystals include the well-known nonlinear CdGeAs2, ZnGeP2, AgGaSe2, GaSe, AgGaS2, and Ag3AsS3 crystals operating in the middle IR range, new mixed AgGaGeS4 and Cd0.35Hg0.65Ga2S4 crystals, two-phase (orange and yellow) HgGa2S4 crystal, and the doped GaSe:In crystal. The mixed crystals and the two-phase HgGa2S4 crystal are transparent in the range from 0.4 — 0.5 to 11.5 — 14.5 μm. The measurements were performed using a pulsed single-mode highly stability TEA CO2 laser with an output pulse duration of ~30 ns. The damage thresholds of new nonlinear AgGaGeS4 and Cd 0.35Hg0.65Ga2S4 crystals and of the HgGa2S4 crystal (the orange and yellow phases) were found to be 1.5 — 2.2 times higher than for the crystals operating in the middle IR range.