Rhenium diselenide as the broadband saturable absorber for the nanosecond passively Q-switched thulium solid-state lasers

The feasibility of using rhenium diselenide (ReSe2) as the saturable absorber for the broadband passively Q-switched (PQS) thulium solid-state lasers was demonstrated in this paper. In the short wavelength of 2 μm region, the combination of Tm:YLF and ReSe2 was used to achieve the PQS operation with multi-wavelength around 1900 nm. A maximum average output power of 862 mw, a shortest pulse width of 527.9 ns and a repetition rate of 54 kHz were obtained. In the long wavelength of 2 μm region, a ReSe2-based PQS multi-wavelength Tm:Y2O3 laser around 2050 nm was realized, generating a maximum average output power of 1.04 W, a shortest pulse width of 727 ns and a repetition rate of 106 kHz. The output performance of the ReSe2-based pulsed laser is competitive among these PQS thulium solid-state lasers using the emerging two-dimensional materials as SAs, indicating that ReSe2 is a promising broadband SA for the 2 μm solid-state lasers.