Tm3+:CaF2 for 1.9 μm laser operation

Tm3+ doped CaF2 single crystals have been grown and studied for their broadband absorption and emission properties. Tunable laser operation was demonstrated for the first time around 1.9 μm. Their spectroscopic investigation shows that rare-earth ions interactions occur at relatively low dopant concentrations, thus favoring 1.9 μm emission, more particularly. As a matter of fact, efficient, tunable, room temperature laser operation is reported around 1.9 μm with a 1.34% Tm3+ doped sample. The crystal was pumped at about 767 nm and the emission wavelength was tuned between 1835 and 1970 nm. A slope efficiency of 41% is achieved with a 10% transmission output coupler.