The first glass polarizer was invented about 30 years ago by Stookey by introducing unique anisotropy in a uniform glass. Major improvement in contrast ratio was made about 10 years ago, when elongation of silver halides precipitates in the glass and subsequent reduction of them was introduced. Since then, high performance polarizers with contrast ratio exceeding 10,000.1 with relatively wide bandwidth have been commercialised. Glass polarizers have been used in isolators in optical telecommunication systems, while application in other areas were previously limited. A recently developed technique by Corning to arbitrarily pattern both Polarized Region and non-Polarized Regions in a single piece of a glass polarizer, Polarcor, is providing opportunities for new applications of the glass polarizers.
