Photonic band gaps of polygonal and circular dielectric rods in square lattices

Abstract

The plane-wave method is employed to determine the band structures and the field patterns of the photonic crystals with polygonal and circular rods in square lattices. Isotropic and anisotropic N-fold polygonal rods are used to assess the effects of the shapes and symmetries of polygonal rods on E- and H-polarization modes. The photonic band structures of the polygonal rods approach those of the circular rods as N increases above a value that is determined by the optical properties of the photonic crystal. Moreover, for comparable geometric structures, anisotropic polygonal-rod photonic crystals can provide larger absolute photonic band gaps than isotropic photonic crystals.