Towards subdiffraction imaging with wire array metamaterial hyperlenses at MIR frequencies.

We describe the fabrication of metamaterial magnifying hyperlenses with subwavelength wire array structures for operation in the mid-infrared (around 3 μm). The metadevices are composed of approximately 500 tin wires embedded in soda-lime glass, where the metallic wires vary in diameter from 500 nm to 1.2 μm along the tapered structure.

Holey fiber mode-selective couplers.

Directional mode coupling in an asymmetric holey fiber coupler is demonstrated both numerically and experimentally for the first time. The holey fiber mode couplers have interesting spectral characteristics and are also found to exhibit increased dimensional tolerances. Following a design based on numerical investigations, a dual-core polymer holey fiber coupler for LP(01) and LP(11) mode multiplexing was fabricated via a drilling and drawing technique.

Refractive index sensor based on a polymer fiber directional coupler for low index sensing.

We propose, numerically analyze and experimentally demonstrate a novel refractive index sensor specialized for low index sensing. The device is based on a directional coupler architecture implemented in a single microstructured polymer optical fiber incorporating two waveguides within it: a single-mode core and a satellite waveguide consisting of a hollow high-index ring. This hollow channel is filled with fluid and the refractive index of the fluid is detected through changes to the wavelength at which resonant coupling occurs between the two waveguides.

Fabricating metamaterials using the fiber drawing method.

Metamaterials are man-made composite materials, fabricated by assembling components much smaller than the wavelength at which they operate (1). They owe their electromagnetic properties to the structure of their constituents, instead of the atoms that compose them. For example, sub-wavelength metal wires can be arranged to possess an effective electric permittivity that is either positive or negative at a given frequency, in contrast to the metals themselves (2).

Multicore composite single-mode polymer fiber.

We study, fabricate and characterize an all-solid polymer composite waveguide consisting of a multicore fiber for single-mode operation down to the visible. The individual cores of the multicore structure are arranged such that they strongly interact, to form the composite core. The behavior and parameters of the multicore geometry are analyzed in order to achieve true single-mode operation.

Stacked-and-drawn metamaterials with magnetic resonances in the terahertz range.

We present a novel method for producing drawn metamaterials containing slotted metallic cylinder resonators, possessing strong magnetic resonances in the terahertz range. The resulting structures are either spooled to produce a 2-dimensional metamaterial monolayer, or stacked to produce three-dimensional multi-layered metamaterials. We experimentally investigate the effects of the resonator size and number of metamaterial layers on transmittance, observing magnetic resonances between 0.

Fluorescent response of dye-filled suspended-core microstructured polymer optical fiber.

Microstructured polymer optical fibers represent quite new technology that is still in the research and development stage. However, some advances and possible applications are available even now. One of these is the possibility of filling the fibers with various fluids to enhance or modify some of their characteristics.

Bend loss in highly multimode fibres.

We investigate the bend loss of highly multimode air-clad microstructured polymer optical fibre which displays low bend loss for small bend radii. After repeated bending the loss approached a plateau, decreasing significantly after a characteristic length. The loss at a particular point depended on the configuration of the fibre preceding that point.

Opening up optical fibres.

A unique optical fibre design is presented in this work: a laterally accessible microstructured optical fibre, in which one of the cladding holes is open to the surrounding environment and the waveguide core exposed over long lengths of fibre. Such a fibre offers the opportunity of real-time chemical sensing and biosensing not previously possible with conventional microstructured optical fibres, as well as the ability to functionalize the core of the fibre without interference from the cladding. The fabrication of such a fibre using PMMA is presented, as well as experimental results demonstrating the use of the fibre as a evanescent wave absorption spectroscopy pH sensor using the indicator Bromothymol Blue.

Microstructured-core optical fibre for evanescent sensing applications.

The development of microstructured fibres offers the prospect of improved fibre sensing for low refractive index materials such as liquids and gases. A number of approaches are possible. Here we present a new approach to evanescent field sensing, in which both core and cladding are microstructured.