The study of the optical nonlinear properties of bulk ZnSe for immersion applications

In this work, we study the nonlinear absorption of ultrashort laser pulses of variable duration (0.3-10 ps) in a bulk polycrystalline ZnSe dielectric. The transmission of the sample was measured for two wavelengths, 515 and 1030 nm, in a wide range of intensities. A nonlinear behavior of the transmission is found when the sample is irradiated with laser radiation at a wavelength of 515 nm with absorption saturation in the region of 3-5 TW/cm². Surface damage thresholds were obtained for a wavelength of 1030 nm for pulse durations of 0.3-10 ps. Keywords: nonlinear ZnSe absorption, solid-state immersion, two-photon absorption, chalcogenide glass surface ablation, ZnSe ablation thresholds.