Electrically‐Switchable Gain in Optically Pumped CsPbBr$_3$ Lasers With Low Threshold at Nanosecond Pumping

Metal halide perovskites hold promise for nonepitaxial laser diodes, yet, continuous-wave (CW) optically pumped (photonic) lasing in CsPbBr$_3$ remains elusive despite its superior thermal- and photo-stability among the perovskite family. This work reports on CsPbBr$_3$ vertical cavity surface emitting lasers with low lasing thresholds (1.3 µJ cm$^{-2}$) at nanosecond pumping and remarkable lasing stability. Furthermore, the electrically switchable gain is achieved in CsPbBr$_3$ electrically assisted optically pumped laser (EAOPL) devices by leveraging ion migration. Applying a small positive DC voltage to the EAOPL device significantly reduces the lasing threshold under nanosecond laser excitation and enhances the cavity mode intensity at CW laser excitation. These findings present a novel strategy, combining a small DC voltage with an electrical pulse, for exploring electrical injection lasing in CsPbBr3 perovskites.