SnS₂ as a Saturable Absorber for Mid-Infrared Q-Switched Er:SrF₂ Laser

Two-dimensional (2D) materials own unique band structures and excellent optoelectronic properties and have attracted wide attention in photonics. Tin disulfide (SnS2), a member of group IV-VI transition metal dichalcogenides (TMDs), possesses good environmental optimization, oxidation resistance, and thermal stability, making it more competitive in application. By using the intensity-dependent transmission experiment, the saturable absorption properties of the SnS2 nanosheet nearly at 3 & mu;m waveband were characterized by a high modulation depth of 32.26%. Therefore, a few-layer SnS2 was used as a saturable absorber (SA) for a bulk Er:SrF2 laser to research its optical properties. When the average output power was 140 mW, the passively Q-switched laser achieved the shortest pulse width at 480 ns, the optimal single pulse energy at 3.78 & mu;J, and the highest peak power at 7.88 W. The results of the passively Q-switched laser revealed that few-layer SnS2 had an admirable non-linear optical response at near 3 & mu;m mid-infrared solid-state laser.