Photonic band gaps in a two-dimensional photonic crystal with open veins

We report two-dimensional (2D) photonic crystals of a square lattice with square dielectric rods growing slender veins on the middle side of each square dielectric rod in air. The complete photonic band gap (PBG) is found in higher index bands. Then extending the length of veins substantially shrinks this PBG, and for an appropriate vein length creates the new complete PBG at lower index bands. But the greatest complete PBG can be gotten where the veins are not fully closed at the lattice unit cell boundary. The photonic band gap is the result of considering the effects of Mie scattering due to the slender veins and interference of electromagnetic waves. Our results may provide a new direction for designing PBG of 2D photonic crystals.