Effects of symmetry breaking of scatterers on photonic band gap in hexangular-lattice photonic crystal

We study the influence of scatterers symmetry on the photonic band gap based on hexangular-lattice photonic crystal. In comparison with the band gap of photonic crystal with five types of different symmetrical scatterers, the number of PBGs of E- and H-polarization obviously increase with breaking the symmetry of scatterers, so that increases the possibility of coinciding with PBGs of E- and H-polarization to form absolute PBGs. For largest absolute PBG, the PBG of E-polarization exhibits red shift with breaking the symmetry of scatterers, but the H-polarization is just the reverse. So their overlap also increases with the breaking the symmetry of scatterers. In addition, by optimizing the parameters (ε, R, r, and θ) of scatterer, we attain number and width of absolute PBG as much as possible.