The third order optical nonlinear character of ZnSe nanocrystals doped silica glasses

ZnSe/SiO2 composites were fabricated with conventional sol–gel synthesis method. The absorption spectra of the semiconductor-doped glasses (SDGs) were presented and compared among different ZnSe doping amounts. The energy gap (E g) decreased distinctly as the content of ZnSe QDs increased. Nonlinear refractive indexes were measured by single beam Z-scan technique. The results revealed that the third order nonlinear susceptibility was efficiently affected by E g, which was explained by local field effect and Kramers–Kronig (KK) relation.