High-repetition-rate ultrafast fiber lasers enabled by BtzBiI: a novel bismuth-based perovskite nonlinear optical material.

Recent advances in perovskite crystals have highlighted their exceptional optical properties, making them promising candidates for a wide range of photonic applications. However, the exploration of high-repetition-rate laser systems based on these materials remains underdeveloped, hindering their potential in ultrafast laser technologies and related fields such as optical communications and precision metrology. In this study, we present, for the first time, the saturable absorption characteristics of a novel organic-inorganic hybrid perovskite incorporating the heavy metal bismuth (Bi), specifically N-methylbenzothiazoleBiI (BtzBiI).