Spectroscopic Characterization and Laser Performance of Diffusion Doped Cr2+:ZnS

Abstract

Spectroscopic, saturation, and laser properties of diffusion doped Cr2+:ZnS crystals synthesized by chemical reaction from gas phase are reported. Lasing was realized with a threshold of 170 µJ and slope efficiency of 9.5% with respect to the 1.5607 µm pump energy, in a hemispherical cavity. Maximum output energy reached 100 µJ. A tuning range of 2.05-2.40 µm was realized, limited by the spectral range of the output coupler of the selective hemispherical laser cavity. Selective cavity experiments used a CaF2 prism as the dispersive element. Findlay Clay losses were found to be about 14%. Absorption cross section (0.80×l0−18 cm2) was estimated from spectroscopic measurements and was in good agreement with saturation data, calculated with the modified Frantz-Nodvik equation for a four level slow absorber.