The research of band gap of 2-D anisotropic dielectric cylinders

The square lattice of isotropic dielectric cylinders in air can not bring about the absolute band gap and the triangular lattice of dielectric cylinders can produce small absolute band gap.In order to get the bigger band gap,the anisotropic material is used instead of the isotropic material, for it can bring about big absolute band gap because of the dielectric constants of the anisotropic material are different in some directions. Based on plane wave method, calculation results show that the width of the absolute band gap for the square lattice is 0.03095ωe. For the triangular lattice the width is 0.03831ωe,which is 3.6 times wider than the absolute band gap produced by the isotropic dielectric cylinders.It is very useful for research of the band gap of photonic crystal.