Study on the structure dependent ultrafast third-order optical nonlinearity of GeS_(2)-In_(2)S_(3) chalcogenide glasses

摘要

The results of the femtosecond time-resolved optical Kerr at 820 nm in GeS_(2)-In_(2)S_(3) chalcogenide glasses indicate that the response time in GeS_(2)-In_(2)S_(3) glasses is subpicosecond, which is predominantly due to the distortion of the electron cloud. The value of (chi)~((3)) in 0.95GeS_(2)-0.05In_(2)S_(3) glass is also as large as 2.7 X 10~(-13) esu, and it reduces with the addition of In_(2)S_(3), which may be ascribed to the microstructure evolution of GeS_(2)-In_(2)S_(3) glasses. It is deduced that the intrinsic [Ge(In)S_(4)] tetrahedral structure units that possess the high hyperpolarizability may do great contribution to the enhancement of third-order optical nonlinearity while [S_(3)Ge-GeS_(3)] ethane-like molecular units make no considerable contribution to that in femtosecond time scale. These GeS_(2)-In_(2)S_(3) and GeS_(2)-In_(2)S_(3)-based chalcogenide glasses would be expected to be the promising materials for all-optical switching devices.