Spectroscopy and lasing of cryogenically cooled Tm3+,Lu3+:CaF2 crystal

The temperature dependence of the spectroscopic and laser properties of a new cryogenically cooled mixed fluoride Tm,Lu:CaF2 crystal was investigated. The influence of optically inactive Lu3+ ions codoping was studied. Efficient 1.9 μm Tm3+ ions lasing at room temperature under 763 nm laser diode pumping was realized. With a temperature decrease down to 78 K the slope efficiency almost doubled up to 66% with respect to 300 K. The wide laser tuning range of 250 nm (1785–2035 nm) was demonstrated.