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

We present a theoretical study of new two-dimensional photonic crystals based on Arckimedean-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 la-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 (similar to 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. (C) 2000 Optical Society of America OCIS code: 030.0030.