Effect of Diffusion Doping of ZnGeP2 with Mg and Ca Atoms on the Optical Properties of Single Crystals

The effect of impurity Mg and Ca atoms on the optical breakdown threshold of a nonlinear ZnGeP₂ crystal at a wavelength of 2.097 μm is studied. An impurity was introduced through diffusion doping by sputtering on a ZnGeP₂ substrate followed by annealing in vacuum at a temperature of 750°C for 200 hours. Mg atoms introduced into a single crystal increase the optical breakdown threshold by 31%. When ZnGeP₂ is doped with Ca atoms, the opposite trend is observed. The changes in the optical breakdown threshold are suggested to occur due to the creation of additional channels for energy dissipation of radiative and fast nonradiative relaxation processes through impurity energy levels. This suggestion requires experimental confirmation. An increase in the optical strength of ZnGeP₂ could expand the scope of its applicability.