Wide angularly isotropic photonic bandgaps obtained from two-dimensional photonic crystals with Archimedean-like tilings

Abstract

We present a theoretical study of new two-dimensional photonic crystals based on Archimedean-like tilings. Three structures are considered: a square lattice with a 4-atom unit cell and triangular lattices with 7- and 13-atom unit cells. A 12-fold local rotational symmetry is obtained for the triangular lattices and is approached for the square lattice. Wide photonic bandgaps can then be achieved, with very weak bandwidth dependence (~1%) on the wave-propagation direction. The complete bandgap frequency is shown to depend on the atomic bond length and not on the crystal period. This new class of periodic photonic crystals is a simple and attractive alternative to photonic quasi crystals.