Third-order optical nonlinearities of chalcogenide glasses within Ge-Sn-Se ternary system at a mid-infrared window

Abstract

Experimental results of third-order optical nonlinearities of chalcogenide glasses (ChGs) within Ge–Sn–Se ternary system at a mid-infrared window of 3 and 3.5 μm are presented in this study. Using femtosecond Z-scan technique, positive nonlinear refractive indexes (n2) of the ChGs were obtained at the mid-infrared wavelengths, with no nonlinear absorption observed. The n2 values at 3 μm were lower than those at 3.5 μm because of the presence of hydroxyl (–OH) group. The maximum n2 was obtained from the Ge–Sn–Se ChGs with highest Sn content, reaching 2.43 × 10−17 m2/W at 3.5 μm, near two times that of As2Se3 glass. Thus, Ge–Sn–Se ChGs can be regarded as a good candidate for photonic devices that operated at mid-infrared window.