CsCl effect on the optical properties of the 80GeS2–20Ga2S3 base glass

Optical properties of chalcogenide glasses belonging to the series (80GeS2–20Ga2S3)100−x(CsCl)x with x=0;5;10;15;20 were investigated. The linear refractive indices (n0) were determined by prism measurements at four wavelengths: 633 nm, 825 nm, 1311 nm, and 1511 nm. Z-scan experiments were performed at 800 nm to measure the non-linear indices (n2) and the absorption coefficients (β). CsCl additions in the base glass (80GeS2–20Ga2S3) are characterized by a white shift of the transmission in the visible range and a strong decrease of both n0 and n2. As the same time, β is also decreasing and this results in a figure of merit FOM=2βλ/n2 that remains relatively low at 800 nm, meaning that this series of highly non-linear glasses should be very suitable for optical switching applications at telecommunication wavelengths.