Effect of Ag addition on the third-order nonlinearity and physicochemical property of chalcohalide glass

In this work, the 70GeS2-20In2S3-10CsI glass introduced with 0-10 mol% Ag2S were prepared by the vacuumed melt-quenching technique. The physicochemical properties, such as glass transition temperature, density, refractive index, transmittance, hardness as well as third-order nonlinearity are investigated with the increasing Ag2S contents. It was found that the refractive index (@632.8 nm), density, and hardness of glasses increase distinctly from 2.204 to 2.270, from 3.520 to 3.675 g cm−3 and from 180.9 to 227.9 kg mm−2, respectively. Meanwhile, the nonlinear refractive index increases from 3.2 × 10−18 to 4.6 × 10−18 m2/W due to the increased refractive index. Finally, the Raman spectra are performed to structurally illustrate the role of Ag addition on the changes of the physicochemical properties. With the Ag2S contents increasing, the vibration intensity of the [InS4] and [InS3I] tetrahedrons increases and the heavy Ag atoms result in the increased density and refractive index, as well as the nonlinear refractive index. The Ag-containing glass, which exhibited good thermal stability, excellent infrared transparency and ultrafast nonlinear optical properties, can be find applications for the IR window material or ultrafast infrared optics.