Ultrafast two-photon optical switch using single crystal hybrid halide perovskites

Photoelectronic performance of organic–inorganic hybrid perovskites has been investigated extensively. Advancement in optoelectronic characterization and application of this group of materials in solar cells, light-emitting diodes, and lasers has been pushed forward rapidly. However, nonlinear optical properties for applications in optical logic devices have not been exploited. Moreover, long-lived excitons and charges limit the response speed of such materials and further construction of ultrafast devices. In this work, we make use of the high third-order optical nonlinearity of ( C H 3 N H 3 ) P b B r 3 single crystals and develop a femtosecond optical switch (OS) based on strong two-photon processes through absorbing one pump and one probe photon. The fascinating band structure, with a steep edge at 2.22 eV between the transmission and strong absorption bands, endows single crystals of ( C H 3 N H 3 ) P b B r 3 with perfect characteristics for two-photon optical switching in the near infrared. An on–off ratio of the probe pulses of about 90% and a speed faster than 400 fs have been achieved for this OS device. To the best of our knowledge, such high efficiency has not been realized for an ultrafast OS with any other materials and devices. Moreover, this is a first exploration, to our best knowledge, of the third-order optical nonlinearity of organic–inorganic hybrid halide perovskites for application in ultrafast optical logic devices with high reliability and low threshold in the near infrared.