Chalcogenide optical fibers for mid-infrared sensing

Abstract

Chalcogenide glasses are a matchless material as far as mid-infrared (IR) applications are concerned. They transmit light typically from 2 to 12 μm and even as far as 20 μm depending on their composition, and numerous glass compositions can be designed for optical fibers. One of the most promising applications of these fibers consists in implementing fiber evanescent wave spectroscopy, which enables detection of the mid-IR signature of most biomolecules. The principles of fiber evanescent wave spectroscopy are recalled together with the benefit of using selenide glass to carry out this spectroscopy. Then, two large-scale studies in recent years in medicine and food safety are exposed. To conclude, the future strategy is presented. It focuses on the development of rare earth-doped fibers used as mid-IR sources on one hand and tellurium-based glasses to shift the limit of detection toward longer wavelength on the other hand.

Infrared fibers

“…Indeed, 2.6 W output at 9.3 μm power was obtained from 7 W input power out of a 1-m-long, 600-μm-diameter unclad TeX fiber provided with an antireflection coating [363]. The long-wavelength transmission Te-ChG fibers has enabled their use for remote chemical analysis/detection and temperature sensing [364][365][366]. The minimum optical loss of unclad Te-ChG fibers (TeAsSe system) is less than 0.1 dB∕m in the 6.7-7.3 μm window [307], while step-index single-mode TeAsSe fibers have a minimum loss of typically ∼0.33 dB∕m at 7.5 μm [367].…”

A new circular chalcogenide/silica hybrid microstructured optical fiber with high negative dispersion for the purpose of dispersion compensation

“…These features make this class of material most suitable for certain applications in optics, such as nonlinear optics, in medicine such as tomography, endoscopy and surgery and in transmission systems such as communication fibers and customized filters [18,19]. The MOFs based on chalcogenide glasses are suitable for power delivery in lasers and the construction biochemical and chemical sensors [20][21][22].…”

Study on optical properties and γ‐ray irradiation resistance of heavy metal oxide tellurite glasses

“…Besides, heavy metals oxides with empty d orbitals, such PbO, Bi 2 O 3 can be easily incorporated into tellurite glasses [4,5]. Moreover, these glassy matrices could be also modified by the addition of different doping ions that impart to the base glass many interesting structural, physical and mechanical features [6][7][8] Doped tellurite glasses are enabling many different applications in optical and telecommunication devices, thin film technology, radiation dosimetry and sensors [9][10][11][12][13][14]. As example, due to the, very large refractive index and third order nonlinearity, these systems could be used for ultrafast switching in optical devices [15].…”

“…In particular, considering the last mentioned application field, tellurite glassy matrices show many advantages on the other kind of glasses (silicates, fluorides, sulphides...) such as ease of forming, not expensive production costs, scarce crystallization tendency [14,19,27], and finally, last but not least, an excellent far infrared transparency (up to around 20 μm) [17,27]. For these reasons, tellurite glasses seem extremely suitable for application as cover glass components for solar cells or space optics, as example [20,28].…”