Precise Control of Single-Crystal Perovskite Nanolasers.

Efficient control of integrated light sources is crucial to advancing practical applications of nanophotonics. Despite the successes of microlasers, their sophisticated nanostructures are inapplicable to nanolasers. The situation for bottom-up synthesized nanolasers becomes more challenging due to the constraints of fixed cavity shapes and fragile material stability. Here we employ the physics of exceptional points (EPs) and demonstrate a strategy to precisely tune the lasing actions in lead halide perovskite nanorods. By placing a nanoparticle to the boundary of a square nanocavity, we show that EPs regularly and controllably emerge as a function of the nanoparticle position. Consequently, both the internal lasing actions and their far-field radiation can be completely reversed with a tiny displacement < 100 nm. The new strategy for controlling lasing actions in nanocavities has been confirmed with numerical simulations and lasing experiments. This research can also bring new avenues for ultrasensitive position sensing. This article is protected by copyright. All rights reserved.