Optical linearity and nonlinearity of ZnSe nanocrystals embedded in epoxy resin matrix investigated by Z-scan technique

The ZnSe nanocrystals were synthesized by hydrothermal method. Through mixed with epoxy resin in vacuum at high temperature environment, the nanocrystals embedded in an epoxy resin matrix structure were obtained. This nanocomposite sample was characterized by transmission electron microscope (TEM) and electron beam diffraction, showing the nanocrystals were dispersed homogeneously and their structures were zinc blende structure. The nanocomposite structure was also confirmed by the blue-shift of the absorption edge. The nonlinear refraction index and two-photon absorption (TPA) coefficient were measured by the Z-scan technique, using a single Gaussian beam of Nd:YAG laser (532 nm). The result shows that ZnSe nanocrystals embedded in epoxy resin matrix have higher nonlinear refraction index and lower TPA coefficient than that of bulk ZnSe.