Study of the nonlinear transmission of Co2+:ZnSe crystals at a wavelength of 1.54 μm

The dependence of nonlinear transmission in Co²⁺-doped ZnSe crystals at a wavelength of 1.54 μm on the incident energy density is studied under the S_ZnSe-S_CoSe-L_Zn-V equilibrium conditions. The obtained results suggest that the residual losses in the crystal at high incident energy densities are not related to absorption from the excited state but are caused by losses appearing probably during sample growing and doping. The saturation energy and the ground-state absorption cross section are determined E_s=0.12 ± 0.03 J cm^-2 and σ = (11 ± 2) × 10^-19 cm².