Efficient lasing of a Cr2+ : ZnSe crystal grown from a vapour phase

The lasing characteristics of a Cr²⁺ : ZnSe crystal grown by the method of free growth on a single-crystal seed using physical transport in helium are studied. The crystal was doped from a vapour phase during its growth. The achieved concentration of dopant Cr²⁺ ions (5×10¹⁸ cm^-3) provides the absorption coefficient of 4.5 cm^-1 at the maximum of the pump band (1.78 μm). Upon pumping by a pulsed Co : MgF₂ laser at 1.67 μm, the slope efficiency equal to 59 % with respect to the absorbed energy was achieved, which corresponds to the quantum efficiency 87 %.