Thermal effects in Cr2+:ZnSe thin disk lasers

We report the modeling and experimental characterization of thermal lensing in Cr²⁺:ZnSe face cooled laser disks using the phase shift interferometry technique. The thermal lens powers of the 1 mm and 0.5 mm thick disks were strong (23 and 7 diopters at 8 W pumping). The thermal lens power scaled with disk thickness and pump power, and temperatures were reached in the disks such that nonradiative relaxation was significant. Laser output greater than 4 W average power was achieved using face cooled thin disks of Cr²⁺:ZnSe.