Ge–As–S chalcogenide glasses with high laser-induced damage threshold at 1.55 μm for acousto-optic applications

Abstract

In this study, two series of Ge–As–S glasses were prepared with compositions of xGeS₂–(100-x)As₂S₃ (x = 20, 38, 56, 74 mol%) and Ge_yAs₁₅S_85-y (y = 21, 25, 30, 35 mol%) to investigate their potential as acousto-optic (AO) materials. The thermal-optic coefficients, acousto-optic and laser-induced damage properties of the Ge–As–S glasses were studied. For the xGeS₂–(100-x)As₂S₃ system, increasing in GeS₂ content led to a decrease in AO figure of merit M₂ and acoustic attenuation, while significantly improving thermal-optic coefficient (dn/dT) and laser-induced damage threshold (LIDT). Conversely, in the Ge_yAs₁₅S_85-y system, increasing Ge content enhanced the AO performance but led to a deterioration in both dn/dT and LIDT. Remarkably, the 74GeS₂–26As₂S₃ glass with outstanding LIDT of 19.31 J/cm² and favorable dn/dT of 20.0 × 10⁻⁶/°C, exceeds three typical commercial As₂S₃, Ge₃₃As₁₂Se₅₅, and As₂Se₃ glasses in terms of performance. The reliable AO properties, low thermal-optic coefficient, and excellent laser damage resistance make Ge–As–S glasses promising for high-power infrared AO devices.