Nanostructured CuO Thin Film for Nonlinear Optical Applications

Nanostructured CuO thin film was deposited on glass substrate using a radio-frequency magnetron sputtering technique. The topological measurements performed by AFM showed the polycrystalline structure of deposited film and the size of CuO nanocrystallites was analyzed. The linear optical absorption of the CuO nanostructured film was studied by UV-Vis spectroscopy and the band-gap energies of indirect and direct transitions were obtained. By performing Z-scan measurements using a picosecond laser the nonlinear absorption coefficient and imaginary parts of the third-order nonlinear susceptibility of the CuO nanostructured film were determined. Nanostructured CuO film exhibited large optical nonlinearity due to saturable absorption caused by electrons filling of excited bands and/or depletion of ground band.