Photorefractive Effect in Organic–Inorganic Hybrid Perovskites and Its Application to Optical Phase Shifter

Abstract Single crystals of methylammonium lead trihalide perovskites with high optical transparency and well‐defined facets are grown via solution process. Using these high‐quality crystals, the photocarrier‐induced refractive‐index change is observed for the first time in organic–inorganic hybrid perovskites. The photorefractive properties are measured using a laser interferometric technique that enables to monitor the time‐resolved refractive phase shifts. It is found that these phase shifts are determined by the initial density of photogenerated carriers and they are surprisingly retained even after carrier recombination. Utilizing the extremely long‐lived phase shift, it is demonstrated that the perovskite single crystal works as a phase shifter of laser light to generate any desired polarization. Furthermore, a periodic polarization‐modulation technique is established using the time‐dependent refractive phase shift. This refractive property can be used for advanced optical applications of organic–inorganic hybrid perovskites.