Study on the third-order nonlinear optical properties of Ni-doped WTe₂ films

Nickel-doped tungsten telluride films (Ni/WTe 2 ) were prepared by direct current-radio frequency (DC-RF) co-sputtering technique, and the doping content of Ni elements in the films was varied by changing the DC target power. We investigated the effect of metal doping and different doping concentrations on the nonlinear absorption and nonlinear refraction of the doped films. The nonlinear absorption coefficients and nonlinear refraction coefficients of the doped films were measured at the 532 nm using the ps Z-scan technique with significant enhancement over the undoped WTe 2 films. It is shown that the saturation absorption effect and self-dispersion effect of WTe 2 film can be effectively tuned by doping transition metal.