966 research outputs found

    Design of microstructured fibers for hollow core guidance

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    Instead of the traditional index guidance, microstructured fibers can guide light in a core of refractive index lower than that of its cladding using mechanisms like photonic band gap guidance, inhibited coupling guidance and anti-resonant guidance. Their guidance is usually leaky and depends on the photonic properties of their structured cladding. Specifically, photonic band gap guidance is possible with photonic crystals, whose photonic band gaps appear below the refractive index index of the core. Guidance in a low-index core or hollow core guidance, is of interest for applications in the fields of bioanalytic, quantum gas, lasers and others that involve interacting of the light with confined matter of low refractive index. My work is aimed at investigating the possibility of hollow core guidance with an all-solid microstructured cladding. Ideally, such a hollow core waveguide is expected to have obvious guidance advantages over capillaries. Besides, it also surpasses the holey hollow core band gap fibers in the optofluidic applications by avoiding undesired penetration of the liquid into the cladding channels. To achieve the design of the ideal hollow core waveguide, I developed two models for all relevant modes in microstructured fibers: an analytical method with binary functions and a reflection-based planar model. While the binary functions for photonic band gap is more about ideal periodic structures extended into infinite, the reflection and transmission analysis with a reflection-based planar model is more practical to be used for waveguides with finite periodic structures and deliberately induced disorder

    Development of Photonic Crystal Fiber Based Gas/ Chemical Sensors

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    The development of highly-sensitive and miniaturized sensors that capable of real-time analytes detection is highly desirable. Nowadays, toxic or colorless gas detection, air pollution monitoring, harmful chemical, pressure, strain, humidity, and temperature sensors based on photonic crystal fiber (PCF) are increasing rapidly due to its compact structure, fast response and efficient light controlling capabilities. The propagating light through the PCF can be controlled by varying the structural parameters and core-cladding materials, as a result, evanescent field can be enhanced significantly which is the main component of the PCF based gas/chemical sensors. The aim of this chapter is to (1) describe the principle operation of PCF based gas/ chemical sensors, (2) discuss the important PCF properties for optical sensors, (3) extensively discuss the different types of microstructured optical fiber based gas/ chemical sensors, (4) study the effects of different core-cladding shapes, and fiber background materials on sensing performance, and (5) highlight the main challenges of PCF based gas/ chemical sensors and possible solutions

    Specialty Photonic Crystal Fibres and Their Applications

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    This book is intended to provide an overview of the state-of-the-art in specialty photonic crystal fiber technology and its multiple applications, combined with an optimistic outlook to what lies ahead. It comprises six original research papers and one review from different leading research institutions worldwide

    Photonic Crystal Fibres for Dispersion and Sensor Applications

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    Enhanced spontaneous raman scattering and gas composition analysis using a photonic crystal fiber

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    Spontaneous gas-phase Raman scattering using a hollow-core photonic bandgap fiber (HC-PBF) for both the gas cell and the Stokes light collector is reported. It was predicted that the HC-PBF configuration would yield several hundred times signal enhancement in Stokes power over a traditional free-space configuration because of increased interaction lengths and large collection angles. Predictions were verified by using nitrogen Stokes signals. The utility of this system was demonstrated by measuring the Raman signals as functions of concentration for major species in natural gas. This allowed photomultiplier-based measurements of natural gas species in relatively short integration times, measurements that were previously difficult with other systems. © 2008 Optical Society of America

    Selective Serial Multi-Antibody Biosensing with TOPAS Microstructured Polymer Optical Fibers

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    We have developed a fluorescence-based fiber-optical biosensor, which can selectively detect different antibodies in serial at preselected positions inside a single piece of fiber. The fiber is a microstructured polymer optical fiber fabricated from TOPAS cyclic olefin copolymer, which allows for UV activation of localized sensor layers inside the holes of the fiber. Serial fluorescence-based selective sensing of Cy3-labelled α-streptavidin and Cy5-labelled α-CRP antibodies is demonstrated

    Photonic Crystal Fibre for Dispersion Controll

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