Tin diselenide as a new saturable absorber for generation of laser pulses at 1μm.

The nonlinear optical responses of two-dimensional (2D) few-layer tin diselenide (SnSe₂) have been investigated in this work. By applying the Z-scan technique, the saturable absorption of SnSe₂ thin film has been observed at a wavelength of ~1μm, which enables SnSe_2, a new saturable absorber for pulsed laser generation. A detailed exploration of the nonlinear absorption of SnSe₂ film and their dependence on excitation pulse energy is carried out. Our results show that saturation intensity of the nonlinear absorption is ~23.78 GW/cm² and corresponding nonlinear absorption coefficients are at a range from -13596 to -2967.3 cm/GW. By employing the SnSe₂-coated mirror as a saturable absorber, the passively Q-switched lasing has been achieved on a crystalline waveguide platform at ~1 μm.