Optically Pumped Mid-Infrared Stimulated Emission of ZnSe:Cr Crystals

We demonstrate that ZnSe:Cr is an excellent solid state laser material for mid-infrared region with a broad amplification band from 2.2 μm to 3 μm, and with a high quantum efficiency of a radiative recombination. 46% external total efficiency and 56 mW threshold power were achieved, when pumped with a CW YAlO:Ho laser at resonant excitation conditions. Such laser system can have widespread applications in medicine as laser scalpels with regulated cutting depth. We further demonstrate a stimulated emission under Cr2+ to 1+ photo-ionization pumping. The latter opens chances for laser emission under carrier injection conditions.