Silica hollow core fibres for mid-infrared medical applications

In this thesis two types of silica hollow core microstructured fibres - the Negative Curvature Fibre and the Photonic Bandgap Fibre - are presented as a novel solution for the flexible delivery of Er:YAG laser radiation. The Negative Curvature Fibre and Photonic Bandgap Fibre had attenuations of 0.06 dB/m and 1.1 dB/m at 2.94 μm wavelength, respectively. This is an important wavelength regime for medical applications, specifically surgery, due to the existence of a strong absorption peak for water around 3 μm. The guidance of high energy pulses of the order of 195 mJ and 14.4 mJ respectively is demonstrated. These energies are sufficient to ablate soft and hard biological tissue. As verification, porcine bone was ablated in air and submerged in water to simulate practical application of a surgical device. The presented fibres are compared to alternative state-of-the-art solid and hollow core fibres, in respect of the fabrication, attenuation, pulse energy delivery capability, bend sensitivity and the output beam profile. The fabrication and characterisation of a novel sapphire endtip is also presented, which seals the hollow cores of the fibres from contamination and therefore increases the usability significantly. The endtip was shown to be mechanically robust, provide a hermetic seal and able to survive practical tissue ablation in air and water. These encapsulated fibres provide a new fully flexible delivery system for high energy Er:YAG laser radiation and hence will open up the possibility of new minimally invasive surgical procedures

Novel Specialty Optical Fibers and Applications

Novel Specialty Optical Fibers and Applications focuses on the latest developments in specialty fiber technology and its applications. The aim of this reprint is to provide an overview of specialty optical fibers in terms of their technological developments and applications. Contributions include:1. Specialty fibers composed of special materials for new functionalities and applications in new spectral windows.2. Hollow-core fiber-based applications.3. Functionalized fibers.4. Structurally engineered fibers.5. Specialty fibers for distributed fiber sensors.6. Specialty fibers for communications

Hybrid photonic-crystal fiber

This article offers an extensive survey of results obtained using hybrid photonic-crystal fibers (PCFs) which constitute one of the most active research fields in contemporary fiber optics. The ability to integrate novel and functional materials in solid-and hollow-core PCFs through various postprocessing methods has enabled new directions toward understanding fundamental linear and nonlinear phenomena as well as novel application aspects, within the fields of optoelectronics, material and laser science, remote sensing, and spectroscopy. Here the recent progress in the field of hybrid PCFs is reviewed from scientific and technological perspectives, focusing on how different fluids, solids, and gases can significantly extend the functionality of PCFs. The first part of this review discusses the efforts to develop tunable linear and nonlinear fiber-optic devices using PCFs infiltrated with various liquids, glasses, semiconductors, and metals. The second part concentrates on recent and state-of-the-art advances in the field of gas-filled hollow-core PCFs. Extreme ultrafast gas-based nonlinear optics toward light generation in the extreme wavelength regions of vacuum ultraviolet, pulse propagation, and compression dynamics in both atomic and molecular gases, and novel soliton-plasma interactions are reviewed. A discussion of future prospects and directions is also included

Semiconductor optical fibres for infrared applications: a review

Over the last decade a new class of optical fibre has emerged that incorporates semiconductor materials within the core. These fibres are rich in optoelectronic functionality and offer extended transmission bands across the infrared spectral region so that their application potential is vast. Various fabrication methods have been developed to produce fibres with a range of unary and compound semiconductor core materials, which can be either amorphous or crystalline in form. This review discusses the main fabrication procedures and the infrared optical properties of the semiconductor fibres that have been fabricated to date, then takes a look at the future prospects of this exciting new technology

Glassy Materials Based Microdevices

Microtechnology has changed our world since the last century, when silicon microelectronics revolutionized sensor, control and communication areas, with applications extending from domotics to automotive, and from security to biomedicine. The present century, however, is also seeing an accelerating pace of innovation in glassy materials; as an example, glass-ceramics, which successfully combine the properties of an amorphous matrix with those of micro- or nano-crystals, offer a very high flexibility of design to chemists, physicists and engineers, who can conceive and implement advanced microdevices. In a very similar way, the synthesis of glassy polymers in a very wide range of chemical structures offers unprecedented potential of applications. The contemporary availability of microfabrication technologies, such as direct laser writing or 3D printing, which add to the most common processes (deposition, lithography and etching), facilitates the development of novel or advanced microdevices based on glassy materials. Biochemical and biomedical sensors, especially with the lab-on-a-chip target, are one of the most evident proofs of the success of this material platform. Other applications have also emerged in environment, food, and chemical industries. The present Special Issue of Micromachines aims at reviewing the current state-of-the-art and presenting perspectives of further development. Contributions related to the technologies, glassy materials, design and fabrication processes, characterization, and, eventually, applications are welcome

Reconfigurable Photonic Crystal Cavities

Photonic crystals are optical structures that contain a periodic modulation of their refractive index, allowing them to control light in recent years of an unprecedented capacity. Photonic crystals may take on a variety of configurations, in particular the photonic crystal cavity, which may “hold” light in small volumes comparable to the light’s wavelength. This capability to spatially confine light opens up countless possibilities to explore for research in telecommunications, quantum electrodynamics experiments and high-resolution sensor applications. However, the vast functionality potentially made available by photonic crystal cavities is limited due to the difficulty in redefining photonic crystal components once they are formed in their (typically) solid material. The work presented in this thesis investigates several approaches to overcome this issue by reconfiguring photonic crystal cavities