Study on correlation between network structure and third-order optical nonlinearity of chalcogenide glasses within a Ge-Sb-S ternary system

In this work, the third-order optical nonlinearity has been characterized in Ge-Sb-S chalcogenide glasses with different atomic ratios. The nonlinear optical parameters were interpreted from structural aspect by the constrained mode as well as Raman spectra, and the contribution of the structure units within the Ge-Sb-S glass network to the third-order optical nonlinearity has been evaluated. When the mean coordination number approaches 2.65, the Ge-Sb-S glass network transits to a rigid 3D phase which gives rise to the rapid augment of the third-order nonlinear susceptibility. Further, we find that the mean coordination number dependent third-order nonlinear susceptibility has a significantly wide variation from 7.92 to 138.78 x 10(-11) esu, showing the great modification flexibility for the nonlinear optical properties of the Ge-Sb-S chalcogenide glasses.