Stable Two-Photon Pumped Amplified Spontaneous Emission from Millimeter-Sized CsPbBr3 Single Crystals

Metal-halide perovskites are promising optical gain materials due to their excellent photophysical properties. Recently, large perovskite single crystals with phase purity, less defects and over millimeter dimensions have been successfully synthesized. However, the optical gain effect has not yet been realized on these large-size single crystals. Herein, we for the first time report efficient two-photon pumped amplified spontaneous emission (ASE) from millimeter-sized CsPbBr3 single crystals (SCs) with a low threshold of 0.65 mJcm^-2 and an optical gain coefficient of 38 cm^-1. Furthermore, the CsPbBr3 SCs also exhibit ultrastable ASE under continuous laser irradiation for more than 40 hours (corresponds to 1.5x10^8 laser shots) at ambient condition. This work suggests the potential application of large-size perovskite single crystals in practical nonlinear optical devices.