Chalcogenide glasses are covalently bonded amorphous compounds containing one or more elements: sulfur, selenium, and tellurium. Other elements found in chalcogenides include arsenic, antimony, and even germanium. Synthetic chalcogenide glasses, like pure germanium, have high refractive indices. Unlike brittle semiconductors, however, they can be precisely molded to specification rather than being built up through crystal growth processes.
Most chalcogenide glasses can transmit the three most important infrared (IR) bands: SWIR, MWIR, and LWIR. However, because they transmit little or no visible light, they appear opaque to the naked eye. Manufacturers can modify the properties of chalcogenide glasses during production to create customized materials for various applications. Depending on the application, optical designers can incorporate germanium and chalcogenide glass into an optomechanical system.
Glass compositions that support multi- or broadband systems will be advantageous as chalcogenide glasses expand into security and sensing applications. As platforms for the use of glass, these materials will need to support a diverse range of manufacturing methods and operate in various environments.
Scientists are increasingly turning to multispectral and hyperspectral imaging to go beyond the limited visible light range. These advanced detector imaging modalities are finding their way into many military and civilian applications, including ballistic missile detection, space-based climate assessment, agricultural crop monitoring, biomedical equipment, and self-driving cars.
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