Inband pumped passively Q-switched Er:YAG laser at 1645Â nm using WS2

A diode-pumped passively Q-switched Er:YAG laser at 1645  nm was demonstrated by using a WS2 saturable absorber (SA). The WS2-SA was prepared by liquid phase exfoliation method and fabricated on a YAG substrate. Under an absorbed pump power of 6.24  W, an average output power of 0.42  W was obtained with a pulse width of 1.8  μs at a repetition rate of 25  kHz, producing a pulse energy of 16.75 μJ.