Experiments investigation of linear and third-order nonlinear optical properties of pure CuO thin film using femtosecond laser pulses

This paper experimentally investigated the linear and third-order optical nonlinearities of a pure CuO thin film deposited on a soda-lime glass substrate. A single-phase film with 62 nm thickness was prepared using the direct current (DC) sputtering deposition process, the film structure was measured using x-ray diffraction (XRD) and a surface profilometer, while the film's linear optical properties were measured using a UV-Vis spectrophotometer. The Z-scan technique was used to measure the nonlinear optical properties of a film that had been irradiated with 100 fs laser pulses using different excitation wavelengths at different incident laser powers. The results showed that increasing the excitation wavelength from 740 nm to 840 nm reduces the nonlinear absorption coefficient of the film from -3.5 x 10(-6) to -2.04 x 10(-6) cm/W, and the nonlinear refractive index n(2) decreases from -4.98 x 10(-18) to -1.2 x 10(-18) cm(2)/W. The optical limiting of the CuO thin film was studied and found to be excitation wavelength dependent with limiting at high incident power. (C) 2022 Optica Publishing Group