Excitation mechanism of blue anti-Stokes and 2.4 μm infrared emission in ZnSe : Cr

Abstract We report the observation and analyze the mechanism of efficient blue anti-Stokes emission in ZnSe : Cr. This emission and the intra-shell transition of chromium Cr 2+ at 2.4 μm are induced by 2+→1+ ionization transition of chromium ions in ZnSe : Cr. The efficiency of the anti-Stokes photoluminescence anticorrelates with the efficiency of the infrared emission. The latter emission dominates at increased temperatures. We conclude that the photoionization excitation mechanism can be applied for optical pumping of 2.4 μm laser action in ZnSe : Cr.