OVERLAPPING TE AND TM BAND GAPS IN SQUARE LATTICE PHOTONIC CRYSTAL OF HOLLOW DIELECTRIC RODS

A numerical study is performed on photonic band gap of 2D square lattice photonic crystal with varied layered dielectric rods by using the plane wave expansion method for the purpose of investigating the effects of geometrical and permittivity variations. The results show that in general the TE and TM band gaps do not coexist in the band structure of this layered rods system. However, for a specific choice of the system parameters leading to a photonic crystals of hollow dielectric rods, both TE and TM photonic band structures feature perceptible band gaps with significant overlap, yielding effective complete photonic band gaps (CPBG). The study further shows that the CPBG can be enlarged by varying both radii of the hollow rods. It is found that a large CPBG can be attained which is comparable in size with those found in hexagonal lattice photonic crystal of air holes as well as square lattice photonic crystal rods incorporating dielectric veins.