Correlation between the nonlinear refractive index and structure of germanium-based chalcogenide glasses

Abstract The nonlinear refractive index ( n 2 ) of new germanium-based sulfo-selenide glasses has been measured at 1064 nm using Z-scan technique, with picosecond pulses emitted by a 10 Hz Q-switched mode-locked Nd:Yag laser. We have determined the impact of the progressive replacement of S by Se on the nonlinear properties of these glasses. The value of n 2 strongly increases with the substitution of S by Se, up to 350 times the n 2 for fused silica. X-ray photoelectron spectroscopy (XPS) indicates that the increase of Ge–Se bond units in the glass network is responsible for the increase of n 2 . The suitability of these glasses for optical switching at telecommunication wavelengths based on such nonlinear properties has been also confirmed.