Solitary plane waves in an isotropic hexagonal lattice

Plane Waves with Negative Phase Velocity in Isotropic Chiral Mediums

The propagation of plane waves in an isotropic chiral medium (ICM) is investigated. Simple conditions are derived — in terms of the constitutive parameters of the ICM— for the phase velocity to be directed opposite to the direction of power flow. It is demonstrated that phase velocity and power flow may be oppositely directed provided that the magnetoelectric coupling is sufficiently strong.

Wideband Dispersion Compensation in Hexagonal Lattice Photonic Crystal Fiber

In this paper, a new structure is provided for the dispersion compensating photonic crystal fibers in order to broaden the chromatic dispersion and increase the dispersion compensating capability in a wide wavelength range. In the structure, putting elliptical holes in the first ring of the inner core clad of a dispersion compensating fiber of the hexagonal lattice, increases the wavelength ran...

Triangular Wavelets: An Isotropic Image Representation with Hexagonal Symmetry

This paper introduces triangular wavelets, which are two-dimensional nonseparable biorthogonal wavelets defined on the regular triangular lattice. The construction that we propose is aimed at preserving isotropy, and a simple nonseparable extension of one-dimensional interpolating wavelets followed by a straightforward generalization. Resulting three oriented high-pass filters are symmetrically...

In-Plane Magnetic Anisotropy in Hexagonal Systems

Observation of topological valley modes in an elastic hexagonal lattice

We report on the experimental observation of topologically protected edge waves in a two-dimensional elastic hexagonal lattice. The lattice is designed to feature K-point Dirac cones that are well separated from the other numerous elastic wave modes characterizing this continuous structure. We exploit the arrangement of localized masses at the nodes to break mirror symmetry at the unit-cell lev...