Room temperature amplified spontaneous emissions in a sub-centimeter sized CsPbBr₃ bulk single crystal

All inorganic perovskite CsPbBr₃ shows great potential in laser device because of its excellent luminescence characteristics, while the room temperature amplified spontaneous emission (ASE) in a large size CsPbBr₃ bulk single crystal is still quite difficult. Herein, we have obtained the room temperature ASE in a sub-centimeter size CsPbBr₃ bulk single crystal pumped with the single-photon excitation. Based on the reproducible light path within the CsPbBr₃ bulk single crystal, the photonic feedback between the bottom and top facets naturally enhances the population inversion, which exhibits an amplified spontaneous emission threshold of ∼320 µJ/cm². The blue shift of the ASE peak along with the increased pumping intensity is also observed and ascribed to the reduction of the refractive index and the energy band filling effect. These findings demonstrate the sub-centimeter size CsPbBr₃ bulk single crystal to be an excellent candidate as an optical gain media for crystal lasers.