Study of the Optical Nonlinearity Characteristics of PbS and ZnS Quantum Dot

Abstract

The optical nonlinear absorption and nonlinear refraction of PbS and ZnS quantum dot was studied by Z-scan under picosecond and femto-second laser pulses. Under the action of picosecond laser pulses, nonlinear absorption coefficient β of PbS and ZnS quantum dot are 7.13×10-14 m/W and 2.04×10-13 m/W; nonlinear refractive index n2 of PbS and ZnS quantum dot are 2.41×10-13 esu and 2.76×10-13 esu; the third order nonlinear susceptibility χ(3) of PbS and ZnS quantum dot are 6.02×10-15 esu and 8.72×10-15 esu. Under the action of femto-second laser pulses, nonlinear absorption coefficient β of PbS and ZnS quantum dot are 8.38×10-13 m/W and 6.99×10-12 m/W; nonlinear refractive index n2 of PbS and ZnS quantum dot are 4.48×10-12 esu and 2.00×10-11 esu; the third order nonlinear susceptibility χ(3) of PbS and ZnS quantum dot are 1.07×10-13 esu and 4.59×10-13 esu. Experiments exhibit that nonlinear optical properties of ZnS quantum dot is better than that of PbS.