Two dimensional photonic band structure: triangular non-Bravais lattice

A triangular non-Bravais lattice was designed. The analysis shows that the crystal constructed from dielectric rods in air background can generate a common band gap for both orthogonal polarizations E and H, and is called absolute photonic band gap, but the crystal constructed from air circular holes in dielectric matrix can not generate an absolute photonic band gap. The effective long-wavelength dielectric constant of this crystal had been calculated using photonic band structure, simultaneously. The results agree with the electrostatic theory well.