Ultrafast nonlinear optical properties of Ag-CdTe thin films by co-sputtering in the near-infrared region

Metal-doped CdTe has become a heated topic in recent years due to its ultrafast nonlinear optical properties. Herein, Ag-CdTe thin films with different doping amount (1W, 3W and 5W) and pure CdTe thin films were fabricated on quartz substrates by magnetron sputtering. The effects of Ag doping on the morphology, optical band gap and nonlinear optical properties of the thin films were systematically investigated. The nonlinear optical properties were investigated by femtosecond(fs) Z-scan technique under 800 nm. The results indicated that the Ag-CdTe thin films exhibit good nonlinear optical properties in the near-infrared region due to free carrier absorption and two-photon absorption. The results showed that the dopant content and the variation of the incident laser energy can control the RSA intensity, the nonlinear absorption coefficient, and the nonlinear refractive index of Ag-CdTe thin films. These results can provide new support for their applications in the field of nonlinear optoelectronic devices.