Optical fibre fluoride

V. Ruddy, S. McCabe and B.D. MacCraith, Detection of propane by IR-ATR in a Teflon-clad fluoride glass optical fibre, Appl. Spectrosc., 44(9) (1990) 1461. 

Praseodymium is used for fluoride-glass optical fibres (Jha et al. 1995). 

Fig. 3. Composite loss spectra for some common IR fibre optics ZBLAN fluoride glass SC sapphire, chalcogenide glass, PC AgBrCl, and hollow glass waveguide plot reproduced from Harrington, 2010.

Examples of optical fibres based on the DSSCs have also been reported (Toivola et al., 2009 Ramier et al., 2008). Recently, a fibre based on a piezoelectric material such as polyvinylidene fluoride has been developed, which can convert both mechanical and light energies (Siores et al., 2010). The authors of the patent claim that the fibre is flexible and can be incorporated into textiles. The commercialisation of these PV fibres is, however, likely to be some time away. 

Optical fibres can be used in the transmittance and ATR mode (a special ATR application is the remote sensor), and even in the reflectance mode. The development of special optical fibres for transmission, transflection or diffuse reflectance measurements favours on-line analysis of problematic product streams and reaction mixtures (solutions, suspensions, emulsions, melts, solids). Both quartz and fluoride (ZrF4-based) glass fibres are used, with the former having poor transmission characteristics above 2000 nm. 

Alternatively, it is possible to install fibre optic probes directly in the main stream in-line while the IR spectrophotometer remains remotely in a low vibration laboratory environment. In-line analysers, which do not remove any sample from the line, have the minimum possible lag time and do not change the sample physically or chemically from its nature in the process. Recently, bundles of 500 /xm optic fibres have been developed for the 5000-900 cm (2000-11,000 nm region), which permit transmission of IR energy over distances of several metres. Lowry et al. [76] have evaluated fibre-optic cables that might prove useful in FTIR remote sampling applications. The various optical fibres (chalcogenide, silver halide, heavy metal fluoride or sapphire) differ in their spectral window [77]. Due to the thermal stability and the spectral window, sapphire fibres are considered suitable for in-line characterisation of polymer melts in a production line (e.g. in an extruder head) as an alternative to discontinu-ously operating conventional off-line transmission IR spectroscopy of polymer films [78]. 

P.W. France, Intrinsic loss measurements, in Fluoride Glass Optical Fibres, Blackie, Glasgow and London, 1990. 

S. Takahashi, Prospects for ultra-low loss using fluoride glass optical fibre a review, J. Non-... 

France PW, Drexhage MG, Parker IM, Moore MW, Carter SF, Wright IV. Fluoride Glass Optical Fibres. London Blackie Son 1990. 

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