Large third-order optical nonlinearities of two-dimensional CsPbBr3 nanoplatelets

Metal halide perovskites show considerable optical nonlinearity and could be used for cost-effective nonlinear optical devices if their nonlinear susceptibilities can be improved. Here, we report large optical nonlinearity, including third-order nonlinear absorption, refraction, and two-photon absorption excited luminescence, of CsPbBr3 nanoplatelets with a thickness of two or three atomic layers and a plane size of about 60 nm. Specifically, the nonlinear absorption was mainly induced by two-photon absorption at low incident powers, and the nonlinear absorption cross section reached 2.15 x 10(7) GM. It is two orders of magnitude larger than that of CsPbBr3 nanocrystals, which makes them an ideal optical limiting material. Furthermore, the nanoplatelets exhibited large self-phase modulation-induced nonlinear refraction, and the figures of merit W and T satisfied W > 1 and T < 1, which allow for optical switching. The large optical nonlinearity of CsPbBr3 nanoplatelets provides a basis for multifunctional applications in nonlinear optical devices. Published under an exclusive license by AIP Publishing.

Automated summary

CsPbBr3 nanoplatelets exhibit large optical nonlinearity, including third-order nonlinear absorption, refraction, and two-photon absorption excited luminescence. The nonlinear absorption cross section is two orders of magnitude larger than that of CsPbBr3 nanocrystals, making them suitable for optical limiting. Furthermore, they show large self-phase modulation-induced nonlinear refraction, allowing for optical switching.