What is chalcogenide glass fiber?

Chalcogenide glass fiber introduction

Chalcogenide glasses are made from mixture of the chalcogen elements: sulfur (S), selenium (Se), and tellurium (Te). The addition of other elements, such as arsenic, germanium, and antimony establish crosslinking between the chains of chalcogens to facilitate stable glass formation. It offers promising properties, such as transmission in the mid and far infrared, low phonon energies, high refractive index, and very large nonlinearities as compared to silica glasses.

Chalcogenide glasses are thermally stable, chemically durable, mechanically flexible, and easily fiberized. The spectral range of infrared transmission of chalcogenide glass fiber (1-12 µm) is much broader than that of silica glass fiber (UV-2 µm). Chalcogenide glass fibers have very high refractive index and very large nonlinearities (1,000 times that of silica fiber), allowing for the development of super continuum in the mid-infrared. Chalcogenide glass fibers are the ideal candidates for mid-infrared applications that require high-power laser delivery, chemical sensing, thermal imaging, and temperature monitoring.

Arsenic-containing chalcogenide glasses, such as arsenic sulfide (As2S3) and arsenic selenide (As2Se3), have excellent chemical and physical properties for active optical devices. The minimum optical loss in As2S3 and As2Se3 are 0.1dB/m between 2 and 10µm.  Among any infrared optical material in use today (silica, fluoride, germanium, zinc selenide, and zinc sulfide), As2S3 glass has the lowest thermal change in refractive index.  For this reason, lenses or windows made from As2S3 glass do not show optical distortion when subjected to the intense IR radiation from lasers such as YAG, ER/YAG or CO.  The low thermal change in refractive index is thought to be the basis for the fact that 700 µm fibers made from As2S3 glass have been reported to transmit more than 100 W of laser energy from a CO laser emitting at 5.4 µm. In short, arsenic-containing chalcogenide, glasses are the most-used material for infrared optical fibers.

Are chalcogenide glass fibers safe to use?

Chalcogenide glasses are very stable.  According to the best of our knowledge, using chalcogenide fibers below 100°C is safe for handling, storage, and transportation. Above approximately 100 ºC, it is recommended to work under fume hood environment.  Chalcogenide glass fibers have high stability to atmospheric moisture and do not crystallize.  The Safety Data Sheet describes chalcogenide glass as nonhazardous and not absorbable through the skin.  For medical applications, there is no data for chalcogenide glass fibers used in vivo.