Enlargement of absolute photonic band gap in modified 2D anisotropic annular photonic crystals

We analyze the absolute photonic band gap in two dimensional (2D) square, triangular and honeycomb lattices composed of air holes or rings with different geometrical shapes and orientations in anisotropic tellurium background. Using the numerical plane wave expansion method, we engineer the absolute photonic band gap in modified lattices, achieved by addition of circular, elliptical, rectangular, square and hexagonal air hole or ring into the center of each lattice unit cell. We discuss the maximization of absolute photonic band gap width as a function of main and additional air hole or ring parameters with different shapes and orientation. ► We consider a certain class of 2D photonic crystals, named modified structures. ► We combine several design techniques for maximizing the photonic band gap. ► We employ the plane-wave method for band structure calculations. ► The results show a remarkable increment in the width of photonic band gap.