A study of nonlinear optical properties in Bi2O3–WO3–TeO2 glasses

Abstract A series of bismuth tungsten tellurite glasses were prepared and their densities, linear refractive indices and transmission spectra were measured. The optical bandgaps E opt and Urbach energies E e of glasses were obtained from ultraviolet absorption edges. Both the optical gap ( E opt ) and the band tail ( E e ) are behaving oppositely. As the value of E opt decreases with increasing WO 3 content, the degree of disorder increases which causes more defects or localized states resulting in deep localized in the bandgap with the tailing increased. Z-scan technique was carried out to investigate the third-order nonlinear optical properties of Bi 2 O 3 –WO 3 –TeO 2 glasses. The third-order optical nonlinearity increases with decreasing the optical bandgap E opt , since a increase of WO 3 content can provide the non-bridging oxygen ion content.