Enhanced nonlinear optical response of Au-doped CsPbI3 quantum dots and its application in all-optical modulation

Perovskite quantum dots (QDs) exhibit significant nonlinear optical (NLO) properties and are considered ideal candidate materials for realizing all-optical device applications. In this work, Au doping is employed to enhance the NLO response of CsPbI₃ QDs, which is systematically investigated using Z-scan, spatial self-phase modulation (SSPM), and white light interferometry (WLI) techniques. The results indicate that under the same laser intensity, Au-doped CsPbI₃ QDs exhibit a larger nonlinear refractive index and more pronounced light modulation refractive index changes compared to pure CsPbI₃ QDs. Based on this enhanced effect, all-optical modulation and optical information conversion were realized in cross-phase modulation (XPM) experiment, using a 532 nm pump laser and a 633 nm probe laser. Moreover, we also optimized the traditional experimental setup to enable a more facile and precise measurement of the time response delay, which is an important parameter in XPM measurements. This work demonstrates that Au-doped CsPbI₃ QDs are promising candidates for efficient all-optical modulation and hold great potential for applications in optical switching and information conversion.