Infrared chalcogen glasses: chemical polishing and fibre remote spectroscopy

Abstract Inorganic vitreous polymers based on the combination of the chalcogen elements Se, Te and As are investigated on account of their unique transparency in the infrared spectral domain leading to applications in night-vision systems as well as in IR remote fibre spectroscopy. An original procedure of chemical polishing using a congruent dissolution process of the glass is developed in order to produce outstanding optical quality surfaces. The same methodology is applied to produce tapered chalcogen glass fibres used as IR evanescent wave chemical sensors. In reducing the fibre diameter by chemical etching, a significant improvement in the sensitivity of the optical sensor operating in the 2 to 12 μm spectral region is observed. This original optical configuration is applied to some in situ chemical or biological analysis.