Four-micron CW operating Dy:PbGa2S4 laser

To promising solid state materials, allowing direct laser emission in mid-infrared atmospheric transparency window from 4 up to 5 µm, belongs a dysprosium doped lead thiogallate crystal Dy
³⁺
:PbGa
2
S
4
.[1] In the first experiments as an excitation radiation source for Dy:PbGa
2
S
4
laser the flash-lamp pumped lasers were used.[2] Improvement of Dy:PbGa
2
S
4
crystal quality enabled to use also low pumping rate source based on diode pumped Nd:YAG laser operating at 1318 nm.[3] Energy up to 90 µJ in 4 ms long pulses (rep. rate 20Hz, mean output power 1.8 mW), was obtained at 4290 nm with slope efficiency 3% with respect to absorbed pumping energy. In present study we demonstrate CW operating Dy:PbGa
2
S
4
laser excited at 1318 nm by diode pumped Nd:YAG.