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 bas ed on Arckimedean-like tilings. Three structures are considered: a square l attice with a 4-atom unit cell and triangular lattices with 7-and 13-atom u nit cells. A la-fold local rotational symmetry is obtained for the triangul ar lattices and is approached for the square lattice. Wide photonic bandgap s 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 ne w class of periodic photonic crystals is a simple and attractive alternativ e to photonic quasi crystals. (C) 2000 Optical Society of America OCIS code : 030.0030.