Sb 2 S 3 as a low-loss phase-change material for mid-IR photonics

We study the mid-IR optical properties of Sb 2 S 3 - a phase -change material (PCM) with high potential for mid-IR integrated photonics. We show that Sb 2 S 3 exhibits a high refractive index contrast n approximate to 1 between its two phases and an extinction coefficient k below 10 - 2 at mid-IR wavelengths (up to similar to 10 mu m). We study the impact of 100 nm Sb 2 S 3 cladding on SiGe-on-Si waveguides and experimentally show that it brings additional propagation loss below 1 dB/cm in the 3.3-3.9 mu m wavelength range in both phases. These findings pave the way for new uses of Sb 2 S 3 in mid-IR integrated photonics. (c) 2024 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement