Perovskite CsPbX3: A Promising Nonlinear Optical Material and Its Applications for Ambient All-Optical Switching with Enhanced Stability

Perovskites are demonstrated as an excellent prospect for applications in all-optical switching due to their excellent nonlinear optical effects. In this contribution, 2D cesium lead iodine (CsPbI 3 ) quantum dots (QDs) and cesium lead bromine iodine (CsPbBr x I 3− x ) nanosheets (NSs) are prepared, characterized, and applied in all-optical switching, and their asymmetric nonlinear optical response is also investigated. Moreover, the impact of the beam distortion on the CsPbI 3 QDs and CsPbBr x I 3− x NSs is systematically analyzed. An all-optical switching technique based on perovskite QDs and NSs is experimentally investigated, which is realized by modulating the propagation of the signal beam with another controlling beam using spatial cross-phase modulation. The achievement of all-optical switching indicates that perovskites can be developed as an excellent optical material for all-optical signal processing. The contribution reveals the potential applications of perovskites as a new type of optical information material, and it is therefore anticipated that CsPbI 3 QDs, CsPbBr x I 3− x NSs, and other 2D perovskite NSs could find promising applications in photonics devices (such as optical modulators, optical switchers, and detectors).