Investigations of structure and nonlinear optical properties of gold doped germanium–gallium–sulfur chalcogenide glasses

• Synthesis of gold doped germanium–gallium–sulfur chalcogenide glasses
• Determination of the role of gold to network structure of Ge–Ga–S glasses
• Performance improvement of optical nonlinearities of Ge–Ga–S glasses after gold doping

Chalcogenide glass in molar composition of Ga10Ge25S65 (GGS) and same glasses doped with various amount of gold were prepared. Both density and refractive index of the glasses increased with increase of gold content. Optical band gap (Eopg) of the GGS glasses was obtained by Tauc and Menth's method, and the Eopg value decreased with increase of gold content. Analysis of Raman spectra informed that the main frame of the glasses was constructed by [GeS4] tetrahedra and no characteristic band belonging to gold was observed, indicating that gold behaved as a glass modifier for the GGS glasses. To investigate the influence the gold has on third-order optical nonlinearities of the GGS glasses, femtosecond Z-scan measurements were conducted at the wavelength of 800 nm. The results showed that the performance of third-order optical nonlinearities of the GGS glasses was improved by introduction of gold.