Cryogenically cooled tunable Tm, Y:CaF2 laser

The goal of this work was an investigation of the temperature influence (80-300 K) on laser properties of thulium doped CaF
₂
, co-doped by yttrium (Tm, Y:CaF
₂
), which could serve as gain medium for generation of radiation at 1.8-2 μm. CaF
₂
single crystal and ceramic belong to promising laser hosts. Its doping by trivalent ions, like Tm
³⁺
, leads to forming of complex structures necessary for charge-compensation. The variety of these centers broaden the absorption and emission spectra, which is favorable to diode pumping and laser tunability. Co-doping by optically inactive Y
³⁺
ions could further increase the variety of optical centers without negative effect of upper laser level concentration quenching. Here we report the first results obtained with Tm, Y:CaF
₂
.