Hollow core fibers

Nemova G, Kashyap R (2006) Modeling of plasmon-polariton refractive index hollow core fiber sensors assisted by a fiber Bragg grating. J Lightwave Technol 24 3789-3796... 

Kadla, J.F. Kubo, S. Venditti, R.A. Gilbert, R.D. Novel hollow core fibers prepared from lignin polypropylene blends. J. App. Polym. Sci. 2002, 85 (6), 1353-1355. 

A major limitation of the sensitivity of this type of sensor is the ability to transfer optical power into the evanescent field. Recent work has incorporated new types of fibers to increase the sensitivity of measurements. Newly developed hollow core fibers, which guide light mainly in the cladding, can be used to couple more power into the sensitive materials [76]. If the hollow core fiber is used as the active sensing area between two silica core fibers, then the transitions between the fibers will force the light to travel from the core into the cladding then back into the core. Another type of fiber is the microstructure fiber or photonic crystal fiber, which incorporates air holes into... 

Zamadar M, Aebisher D, Greer A (2009) Singlet oxygen delivery through the porous cap of a hollow-core fiber optic device. J Phys Chem B 113 15803—15806... 

Fig. 4. Coexisting vapour-grown carbon fiber, with thicker diameter and hollow core, and carbon nanolubes, with thinner hollow core, (as-grown samples).

Renn, M. J. Pastel, R. Lewandowski, H. J., Laser guidance and trapping of mesoscale particles in hollow core optical fibers, Pkys. Rev. Lett. 1999, 82, 1574 1577... 

Lehn and coworkers also discussed the principles of design of self-assembling helical structures on the basis of conformational control. Depending on the solvent used, they were able to obtain helicate fibers and bundles possessing extended molecular channels characterized by hollow cores of limited diameter ofca. 8 A. This finding could form the basis of functional materials for multichannel ion active transport [28]. 

Hollow fibers have been tried as liquid-core fibers in spectrophotometry [118] and porous fibers have been well adapted for gas measurements [119,120]. The latter are made of porous polymers, which can trap indicators or reagents in the matrix with a very high permeability of gases and liquids. For liquid applications, porous silica gel has also been used [121],... 

Flax. Flax is also a cellulosic fiber but has a greater degree of crystallinity than cotton. The morphology of flax is quite different from that of cotton. Flax fibers have a long cylindrical shape with a hollow core. The fibers range in length from V2 to 2V2 inches, with a diameter of 12 to 16 microns. Flax staple is comprised of bundles of individual fibers. Historians believe that flax was among the first fibers to be used as... 

Yan H, Gu C, Yang C et al (2006) Hollow core photonic crystal fiber surface enhanced Raman probe. Appl Phys Lett 89 204101... 

Hollow membrane fibers are required for many medical application, e.g. for disposable dialysis. Such fibers are made by usmg an appropriate fiber spinning technique with a special inlet in the center of the spinneret through which the fiber core forming medium (liquid or gas) is injected. The membrane material may be made by melt-spinning, chemical activated spinning or phase separation. The thin wall (15-500 xm thickness) acts as a semi-permeable membrane. Commonly, such fibers are made of cellulose-based membrane materials such as cellulose nitrate, or polyacrylonitrile, polymethylmethacrylate, polyamide and polypropylene (van Stone, 1985). 

With respect to conventional fiber, the potential benefits of a hollow-core photonic crystal fiber are lower transmission losses (due to both reduced absorption and Raleigh scattering) and lower nonlinearities, since the core is air. In only a few years of research, interest in this area has led to remarkably low-loss fibers (13 dB/km at 1500 mn 100 m length)." With continued advances toward lower-loss photonic crystal fibers, efforts also have begun to address field-level issues, including microbend losses" " and fiber splicing." ... 

Sensing Using Hollow-Core Photonic Bandgap Fibers. 49... 

Recently, novel type of optical fibers, called hollow-core PEG fibers, has been introduced. In their cross section, PEG fibers can contain periodically arranged micron-sized air voids [31, 46, 53] (Fig. 2a), rings of holes separated by nanosupports [4, 61] (Fig. 2b), or a periodic sequence of micron-sized layers of different materials [45, 57] (Fig. 2c). PEG fibers are currently available in silica glass, polymer, and specialty soft glass implementations. The key functionality of such... 

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