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

摘要

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.