CH₃NH₃PbI₃ perovskite thin films as a saturable absorber for a passively Q-switched Nd:YAG laser

In this study, we experimentally demonstrated the fabrication of a passively Q-switched Nd:YAG laser using a hybrid organic-inorganic methylammonium lead halide (CH₃NH₃PbI₃) perovskite as a saturable absorber (SA). The broadband linear transmittance in the 0.3-1.1 μm range and the nonlinear optical absorption at 1064 nm were measured. The CH₃NH₃PbI₃ SA exhibited large nonlinear saturable absorption with a modulation depth and saturation intensity equal to 3.9% and 6.5 MW cm^-2, respectively. Using the CH₃NH₃PbI₃ SA, a stable Q-switched laser operation with a maximum average output power of 388 mW corresponding to a pulse width of 192 ns was achieved. Thus, the CH₃NH₃PbI₃ film is an efficient SA candidate for stable lasers and has great potential as a broadband nonlinear optical material for ultrafast photonics.