Optical bistability in layered InSe crystal

In this study, we experimentally study the dependence of the intensity of laser radiation incident on and transmitted through a layered InSe crystal. A picosecond YAG:Nd[Formula: see text] laser with a parametric light generator was used as a light source, making it possible to generate light pulses with a duration of [Formula: see text]30 ps, tunable in frequency within the range of 0.75–[Formula: see text]m. Optical bistability in the region of exciton resonance was detected in an InSe crystal at room-temperature under the picosecond YAG:Nd laser. It is shown that the decrease in absorption in the exciton resonance region is associated with the process of exciton–exciton interaction, shielding of excitons, and the Mott transition.