Hybrid Q-switched laser with MoS₂ saturable absorber and AOM driven sub-nanosecond KTP-OPO.

Two-dimensional (2D) materials, especially transition-metal dichalcogenides, such as molybdenum disulfide (MoS₂) and tungsten disulfide (WS₂), have attracted great interests due to their exceptional optical properties as saturable absorbers in laser systems. In this work, at first, we presented a diode-pumped passively Q-switched laser with MoS₂ saturable absorber (MoS₂-SA). At an incident pump power of 6.54 W, a maximum output power of 1.15 W with a minimum pulse duration of 70.6 ns was obtained, which is the shortest pulse duration of diode pumped passively Q-switched laser with MoS₂-SA to the best of our knowledge. Then, by using a hybrid Q-switched laser with a MoS₂-SA and an acousto-optic modulator (AOM) as pumping fundamental laser, a sub-nanosecond KTiOPO₄ (KTP) based intracavity optical parametric oscillation (IOPO) was realized. With an incident pump power of 10.2 W and AOM repetition rate of 10 kHz, the maximum output power of 183 mW with minimum pulse duration of 850 ps was obtained. The experimental results indicate that the IOPO pumped by the hybrid Q-switched laser with AOM and MoS₂-SA can generate signal wave with shorter pulse duration than those IOPOs pumped by hybrid Q-switched laser with AOM and Cr⁴⁺:YAG or single-walled carbon nanotube saturable absober (SWCNT-SA) or monolayer graphene SA.