Three-photon absorption in ZnO film using ultra short pulse laser

The three-photon absorption (3PA) in nanostructure wide-band gap ZnO semiconductor material is observed under high intensity femtosecond Titanium-Sapphire laser of 800 nm wavelength excitation. The ZnO film was prepared by chemical spray pyrolysis technique with substrate temperature of 400 o C. The optical properties concerning the absorption, transmission, reflection, Raman and the photoluminescence spectra are studied for the prepared film. The structure of the ZnO film was tested with the X-Ray diffraction and it was found to be a polycrystalline with recognized peaks oriented in (002), and (102). The measured of three photon absorption coefficient was found to be about 0.0166 cm 3 /Gwatt 2 , which is about five times higher than the bulk value.