Role of powder handling on resulting impurities in ZnSe-doped As-S-Se composite materials

Abstract

Optical composite materials made by powder processing routes can suffer from unwanted absorption loss introduced through powder handling. This can be due to impurities that are introduced during different stages of a powder processing protocol such as mixing, sieving, or grinding. The present work has evaluated the prevalence of impurities imparted to powders used to create an optical composite comprised of an As-S-Se chalcogenide base glass and ZnSe powders. The goal of this study was to identify a suitable powder handling protocol that demonstrates control of the starting particle sizes of the refractive index matched glass matrix and dopant ZnSe to acceptable levels and minimizes adverse impurities that can create loss in a glass-ceramic composite preform and envisioned fiber preforms, and fibers formed from them. Employing a heat treatment step under vacuum prior to re-melting glass powders was shown to reduce the concentration of key impurities, OH-, S-H, and Se-H, by 45.0%, 31.1% and 21.2%, respectively, as compared to re-melted material made from powders without specialized handling.