Dy-doped CaF 2 transparent ceramics as a functional medium in the broadband mid-infrared spectral region

Highly transparent Dy:CaF2 ceramics with various doping concentrations were fabricated by a hot isostatic pressing (HIP). Their optical properties, emission cross-sections, and saturable absorptivities were evaluated to examine their use as a new candidate 3-μm laser functional medium. Based on those evaluations, we demonstrated passively Q-switched operation of a 2.92-μm Er:YAP laser using a Dy:CaF2 ceramic as a saturable absorber.