Nonlinear Refraction of Nd~(3+)- Li~+Co-Doped CdS-PVP Nanostructure

摘要

Third-order optical nonlinearity of the co-doped CdS nanoparticles embedded in polymer thin films is studied with the Z-scan technique with 632.8 nm excitation using a cw laser. The results show that the co-doped CdS nanocomposite film exhibits enhanced negative nonlinear refractive index in the order of n_2 ≈10~(-5) cm~2/ W, as compared to the undoped CdS nanoparticles. Nonlinear refractive index of co-doped CdS-PVP thin film are found maximum for the sample doped with 5 wt% of Nd~(3+)-Li~+ concentration. The underlying mechanism is discussed.