Spiral three-dimensional photonic-band-gap structure

We found a general type of microscopic structure that can be arranged into various types of lattice to create photonic crystals with sizable band gaps. We arranged spiral-shaped rods into three types of lattice: simple cubic, face-centered cubic, and body-centered cubic; we then calculated the band structures of these dielectric structures by means of a plane-wave expansion. Our results show that there exists a gap as large as 28% for dielectric contrast of 12.25:1.