Non-linear optical properties of chalcogenide glasses measured by Z-scan

To explore the potentialities of chalcogenide glasses for ultrafast optical switching, the non-linear refractive indices of different compositions are measured. Several binary glasses in the [Ge–Se] system, As2S3 and As2Se3 glasses, as well as ternary glasses in the [Ge–Se–As] system have been characterized. Non-linear measurements have been performed by the Z-scan technique, at different intensities, with the picosecond pulses emitted by a 10 Hz Q-switched mode-locked Nd-YAG laser at 1064 nm, in adequate conditions to characterize ultrafast non-linearities. Non-linear refractive indices as high as 22×10−18 m2/W have been obtained in the ternary system. In the case of As2S3 and As2Se3 glasses, a significant variation of the value of the non-linear index of refraction with the laser intensity has been observed which is attributed to a fifth order non-linearity.