Cation-exchange synthesis and measurement of PbS quantum dots with high nonlinear optical properties

摘要

PbS quantum dots with nearly monodisperse size (similar to 3.8 nm) were successfully fabricated via a cation-exchange method, and were investigated by the z-scan technique with 532 nm laser radiation. The PbS quantum dots exhibited high optical nonlinearity with nonlinear absorption coefficient, nonlinear refractive index, and nonlinear susceptibility of 2.93 x 10(-9) m/W, 1.12x10(-9) esu, and 1.90 x 10(-10) esu, respectively, and with optical limiting threshold value of 1.5 J/cm(2) under experimental conditions.