For some twenty plus years, infrared glasses have been one of the coming new materials. They have always had a lot of promise but, except for some military applications of bulk components, infrared glasses have not been commercialized. There is now a new wave of attempted commercialization with groups in France, and the USA building embryonic businesses in heavy metal fluoride fibers, and groups in Japan, USA, and Russia beginning to develop marketable chalcogenide fiber. Some work is also being done with modeled chalcogenide glass lenses. The major applications for the fiber are chemical sensing (spectroscopy), temperature sensing (pyrometry), and low-level laser power delivery. Telecommunications and long lengths of ultra-low loss fiber are not a significant factor in today's market, indeed the loss requirements for most applications are in the 100s of dB/km. Even at those levels, however, heroic efforts of raw material purification are often required to obtain the necessary properties. All infrared glasses have characteristics that make them more difficult to work with than conventional glasses. Against this is the advantage that these materials, to a greater or lesser extent, transmit in the infrared region of the spectrum and may be used to make fibers or optical components with characteristics that are otherwise not available.
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