Low-Threshold and Ultrastable Amplified Spontaneous Emission from CsPbBr₃@Glass via Glass Network Modulation

Inorganic lead halide perovskite quantum dot (QD)-embedded glasses with exceptional optical properties and stability are promising optical gain media for laser applications, but their amplified spontaneous emission (ASE) typically occurs at high pumping thresholds. Here, we report a glass network modulation strategy for low-threshold ASE from CsPbBr₃@glass. By adding ZrO₂ to enhance the glass network polymerization, high-quality and compact growth of QDs inside glass is promoted rather than uncontrolled self-crystallization. Transient absorption measurements reveal that this method reduces carrier trapping, inhibits biexciton Auger recombination, and accelerates hot exciton cooling, enabling efficient population inversion. Consequently, the CsPbBr₃@glass exhibits a record-low ASE threshold of 54.5 μ J cm^-2 and a high net modal gain coefficient of 394.4 cm^-1 under femtosecond pulse excitation, together with quasi-continuous ASE realized using nanosecond laser pumping. Notably, our CsPbBr₃@glass is orders of magnitude more stable than their colloidal counterparts for ASE under identical excitation conditions. This study underscores the potential for developing high-performance lasers using glass-protected perovskite QDs.