Inevstigation the effect of shapes, size, and orientation of dielectric rods on the photonic bandgap for various lattices in 2D anisotropic photonic crystals

Abstract

The photonic band structures of two-dimensional anisotropic photonic crystals have studied by solving Maxwell's equations with use of the plane-wave expansion method.We have calculated the photonic band structure for electromagnetic waves in a structure consisting of a periodic array of parallel dielectric rods of various cross sections, whose intersections with a perpendicular plane form a different shape of lattice. We considered three type of lattice (triangular, square and Hexagonal) with anisotropic tellurium rods in air background with different geometric shapes (oval, circle, square, hexagon and rectangle). The photonic band gap can be further maximized by adjusting the orientation and size of the tellurium rods. The numerical results show that the overlap photonic band gap (PBG) between the TM and TE gaps (polarization-independent PBG) is the largest for a triangular lattice of oval rods with orientation.The overlap PBG for a square lattice of rectangular rod with orientation is the next largest.An important result is that compared to isotropic photonic crystals, which maximum photonic band gap is achieved by selecting a rod of the same symmetry with lattice; this inference is not true in the case of anisotropic crystals.