Hollow-core photonic crystal fiber

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

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." ... 

Smolka S, Barth M, Benson O (2007) Highly efficient fluorescence sensing with hollow core photonic crystal fibers. Opt Express 15 12783-12791... 

Fig. 2 Various types of hollow-core photonic bandgap fibers, (a) Photonic crystal fiber featuring small hollow core surrounded by a periodic array of large air holes, (b) Microstructured fiber featuring medium-sized hollow core surrounded by several rings of small air holes separated by nano-size bridges, (c) Bragg fiber featuring large hollow core surrounded by a periodic sequence of high and low refractive index layers...

Konorov SO, Fedotov AB, Zheltkov AM, Miles RB (2005b) Phase-matched four-wave mixing and sensing of water molecules by coherent anti-Stokes Raman scattering in large-core-area hollow photonic-crystal fibers. J Opt Soc Am B 22 2049-2053... 

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... 

Keywords Absorption ARROW waveguide Biosensor Chemical sensor Confinement Dielectrics Evanescent field Fiber optics Fluorescence Hollow core Liquid-core Loss Optical mode Photonic crystal Refractive index Resolution Scattering Sensitivity Total internal reflection Waveguide... 

---