Ultrafast All-Optical Tuning of Fano Resonant Halide Perovskite Nanoparticles

A new paradigm for active nanophotonic structures and metadevices based on perovskites has recently emerged due to several unique features of these materials such as room-temperature exciton, tunable bandgap energy, and low-cost fabrication methods [1,2]. Progress towards future applications requiring dynamical control of the optical response will depend on our understanding of photoexcitations in these systems [3,4]. In this work, we report the first experimental observation of ultrafast all-optical modulation of Fano resonant halide perovskite nanoparticles (NP). Our measurements, corroborated by analytical and numerical models, show that the out-of-equilibrium dynamics of these systems can be thoroughly controlled by engineering the NP size.