Gilles Fonteneau

Infrared glass fibers for in-situ sensing, chemical and biochemical reactions

Infrared optical fibres based on chalcogenide glasses have been designed for evanescent wave spectroscopy. The sensitivity of the optical sensor is improved in tapering the sensing zone by chemical etching and the working optical domain of the system has been tested on a chloroform sample. This original remote sensor, based on the analysis of infrared signatures, has been applied to follow the fermentation process in cider fabrication as well as to detect and monitor a bacterial biofilm.

New fluoride glasses based on 4f and 5f elements

Abstract New fluoride glasses have been isolated in the ternary systems ThF 4 -LnF 3 -BaF 2 with Ln = the lanthanides Yb, Y, Tm. The melt must be quenched to reduce crystallization. They are simply prepared from oxides by an appropriate NH 4 F, HF treatment. The IR transmission is remarkable, the optical window lying in the 0.25-10 μm region.

Recent developments in chemical sensing using infrared glass fibers

Infrared (IR) optical fibers based on chalcogenides have been investigated to optimize their response when they are used as evanescent wave chemical sensors. The fiber sensing part diameter can be reduced by tapering the fiber during the drawing process or by chemical polishing. The resulting fiber allows the achievement of a detection probe that has been tested in several experimental conditions. Among them, it is verified that these chalcogenide-based fibers are not sensitive to microwave irradiations and give on-line IR spectra from which kinetics and reaction mechanisms inside a microwave oven can be determined.

Une nouvelle famille de verres fluores transmetteurs dans l'infrarouge: Fluorures vitreux dans les systemes ThF4BaF2MF2 (M = Mn, Zn)

Abstract A new family of fluoride glasses based on ThF 4 has been isolated in the ternary systems ThF 4 BaF 2 MnF 2 and ThF 4 BaF 2 ZnF 2 . These glasses have a good I.R. transmission: the absorption edge in the 9 μ region indicating that they are different from the ZrF 4 based glasses. To be stabilized, they must be quenched.

Tellurium halide glasses. New materials for transmission in the 8–12 μm range

A new class of IR transmitting glasses has been discovered in the binary systems TeCl and in the ternary systems TeClS, TeClSe, TeBrSe, TeBrS, TeBrSe; TeBrS and TeISe. The ternary glasses have a very high resistance towards devitrification. These so-called “TeX glasses” have a glass temperature Tg ranging from 50°C to 85°C depending on the composition. The S or Cl containing glasses have their IR edge located in the 13 μm region while the compositions not containing these light elements have their multiphonoedge near 18 μm. A typical glass composition such as Te3Br2 has a potential high transparency of about 10 dB/km at 10.6 μm estimated from band-gap and multiphonon absorption. Samples prepared from high purity compounds show no parasitic absorption bands due to OH, SH and other complex anions. Vitreous domains, preparation conditions and some properties such as thermal expansion and resistance to corrosion by water are discussed.

Infrared chalcogen glasses: chemical polishing and fibre remote spectroscopy

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.

New zirconium free multicomponent fluoride glasses

Abstract Systematic investigations of indium based heavy metal fluoride glasses have led to the discovery of a fluoride composition with a low devitrification rate. The glass BIZYbT with the composition 30 BaF 2 −30 InF 3 −20 ZnF 2 −10 YbF 3 −10 ThF 4 is characterized by a difference Tc−Tg = 123° C and an I.R. multiphonon edge lying in the 8 μm region, about 1 μm longer than for the fluorozirconate. Investigations of the T.T.T. curve and various optical properties indicate that this composition is a good candidate for I.R. fluoride fibers of wide transmission range.

Nouveaux verres fluores transmetteurs dans l'infrarouge dans les systemes LnF3BaF2ZnF2

Abstract A new family of fluoride glasses have been isolated in the ternary systems LnF 3 BaF 2 ZnF 2 with Ln = rare earth and yttrium. The melt must be quenched to reduce the crystallization. These glasses have a good I.R. transmission: the absorption edge is in the 9 μ region.

Stabilization of heavy metals fluoride glasses

A new class of fluoride glasses has been isolated in the ternary system containing one transition metal fluoride ZnF2, one rare earth fluoride YbF3 and one actinide fluoride ThF4. The controlled addition of BaF2 playing the role of modifier allows the stabilization of glasses with low rate of crystallization in the quaternary system BaF2ThF4ZnF2YbF3. The infrared transmission can be extended to the 7–8 μ region, a significant improvement over the fluorozirconate glasses.

Comparative study of BaF2/ThF4 glasses containing YF3, YbF3 and LuF3

Abstract A series of glasses of composition (mol %) (x)BaF 2 − (33.3−x/3)ZnF 2 − (33.3−x/3) − (33.3−x/3)ThF 4 , where M = Y or Yb and x = 10–25 were synthesized. Optical, thermal and microhardness measurements were made and the data compared with that for fluorozirconate, fluorohafnate, and glasses where M = Lu. The subject materials have higher glass transition and crystallization temperatures, higher hardness and somewhat lower UV absorption coefficients than typical ZrF 4 /HfF 4 -based glasses.