Continuous wave and ReS2 passively Q-switched Er : SrF2 laser at ∼3 μm

We report on an efficient Er:SrF2 laser at 2.79 μm. A continuous wave output power of 1.06 W was obtained with a slope efficiency of 41%, significantly exceeding the Stokes efficiency of 35%. Stable Q-switched laser operation was realized by using an ReS2 saturable absorber, generating an average output power of 0.58 W with a pulse duration of 508 ns at a repetition rate of 49 kHz, corresponding to a pulse energy of 12.1 μJ.