“Reporting on the latest advancements in optoelectronics, researchers have synthesized formamidinium lead bromide (FAPbBr3) nanocrystals (NCs) with varying sizes using ligand-assisted precipitation (LARP) technology at room temperature. These NCs exhibit remarkable two-photon pumped amplified spontaneous emission (ASE) properties, with a large two-photon absorption coefficient and high non-linear absorption cross-section. The study, which utilized photoluminescence and time-resolved photoluminescence spectroscopy to characterize ASE properties and Z-scan technique and two-photon excited fluorescence method to study nonlinear optical properties, demonstrates that FAPbBr3 NCs could be a promising green-emitting frequency-upconversion material for high-performance two-photon pump lasers.”