Effect of the Stoichiometry of As2S3 on the Optical Transmission of Glass in the 5–8 µm Spectral Range

Abstract

Glassy chalcogenides A^VB^VI obtained by solidification of high-temperature melts inherit the polymolecular nature of the melt. The influence of this circumstance on the optical properties of glasses is important for the fabrication of optical fibers and has not been adequately studied. Bulk samples of high-purity As_40 – xS_60 + x glasses (0 < x < 5) containing less than (1–2) × 10^–5 wt % metal and silicon impurities and not more than (0.5–1) × 10^–4 wt % carbon, oxygen, and hydrogen compounds were manufactured, and optical fibers were fabricated from these materials. The IR spectra of 12 cm-long bulk samples and optical fibers of up to 15 m length were recorded in the 1000–2000 cm^–1 spectral range. The spectra of the bulk samples and the optical fibers showed absorption bands with maxima at 1950, 1805, 1460, and 1320 cm^–1, due to the presence of super-stoichiometric amount of sulfur in the glass. The corresponding extinction coefficients were determined. The results of the study indicate that the stoichiometry of As₂S₃ can be considered as a factor significantly affecting the optical characteristics of glass.