Nonlinear optical characterization and measurement of optical limiting threshold of CdSe quantum dots prepared by a microemulsion technique

Abstract

CdSe quantum dots prepared by micro emulsion technique shows quantum confinement effect and broad emission at 532 nm. These quantum dots have about 4.35 nm size, and they exhibit good nonlinear effects which are measured using z-scan technique. The samples have a reverse saturation in the nonlinear absorption as nonlinear optical absorption coefficient β is 2.545 × 10−10 W m−1 and nonlinear optical refraction coefficient n2 is −1.77 × 10−10 esu. The third-order nonlinear optical susceptibility is found to be 4.646 × 10−11 esu and also the figure of merit is 2.01 × 10−12 esu m. The optical limiting threshold which is found to be 0.346 GW/cm2 makes it a good candidate for device fabrication.