A kind of saturable absorber (SA) based on layered MoSe ₂ nanosheets has been fabricated successfully by an ultrasound-assisted liquid phase exfoliation method. The as-prepared MoSe ₂ SA was characterized and employed as Q-switch in a diode-pumped Tm-doped crystalline all-solid-state laser at around 2 μm. A stable passively Q-switched 2 μm laser with a maximum pulse repetition rate of 158 kHz and a minimum pulse width of 520 ns was successfully realized. A maximum average output power of 1.19 W, corresponding to a maximum pulse energy of 12.7 μJ and pulse peak power of 21.8 W, has been obtained. It was the first demonstration of MoSe ₂ SA in realizing a solid-state 2 μm pulsed laser, to the best of our knowledge. The results confirmed the excellent ability and promising potential of MoSe ₂ SA as an optical modulator in generating high repetition rate and short pulsed laser at the midinfrared spectral band.

A diode-pumped passively Q-switched and mode-locked Nd:GdVO₄ laser at 1.34 μm with V³⁺:YAG as the saturable absorber is realized in a V-type folded cavity. About 100% modulation depth of mode locking can be obtained as long as the pump power reaches the oscillation threshold. The width of the mode-locked pulse is estimated to be less than 280 ps with 200 MHz repetition rate within an about 980 ns-long Q-switched pulse envelope. A maximum output power of 200 mW and Q-switched pulse energy of 5.7 μJ is obtained.

A diode-pumped passively Q-switched mode-locked (QML) intracavity frequency-doubled Nd:GdVO4/KTP green laser with a semiconductor saturable absorber is presented. Nearly 100% modulation depth for the...