Broadband robustly single-mode hollow-core PCF by resonant filtering of higher-order modes.

We report a hollow-core photonic crystal fiber that is engineered so as to strongly suppress higher-order modes, i.e., to provide robust LP single-mode guidance in all the wavelength ranges where the fiber guides with low loss.

Curvature-induced geometric momenta: the origin of waveguide dispersion of surface plasmons on metallic wires.

We show that the propagation of surface plasmon polaritons (SPPs) on metallic wires is governed by two solely curvature-induced geometric momenta, leading to a significant modification of the waveguide dispersion, i.e. a change of their phase velocity.

As₂S₃-silica double-nanospike waveguide for mid-infrared supercontinuum generation.

A double-nanospike As2S3-silica hybrid waveguide structure is reported. The structure comprises nanotapers at input and output ends of a step-index waveguide with a subwavelength core (1 μm in diameter), with the aim of increasing the in-coupling and out-coupling efficiency. The design of the input nanospike is numerically optimized to match both the diameter and divergence of the input beam, resulting in efficient excitation of the fundamental mode of the waveguide.

Polarisation-resolved near-field mapping of a coupled gold nanowire array.

We report direct observation of the 2D transverse near-field intensity and polarisation distribution of surface plasmon polaritons guided on metal nanowires. Quadrupolar modes are excited on an array of coupled nanowires arranged around the central glass core in a photonic crystal fibre, with lobes whose orientation depends on the polarisation state of the launched core light. The radial electric field is resolved using a polarization sensitive near-field probe in light-collection mode.

Bandgap guidance in hybrid chalcogenide-silica photonic crystal fibers.

We report a hybrid chalcogenide-silica photonic crystal fiber made by pressure-assisted melt-filling of molten glass. Photonic bandgap guidance is obtained at a silica core placed centrally in a hexagonal array of continuous centimeters-long chalcogenide strands with diameters of 1.45 μm.