A hollow spherical non-closed-packed face-centered cubic uniaxial structure with a photonic band gap

A calculation of band structure is carried out and demonstrates that a hollow spherical non-closed-packed face-centered cubic uniaxial structure possesses a robust complete photonic band gap between the low-frequency bands (2nd and 3rd bands). The results show that the relative gap size can reach a value of 6.1% at a low dielectric contrast of 7.84 appropriate to the transparent TiO2. The influence of structure variations on the band gap, such as hollow spheres, cylindrical tubes and dielectric contrast, is also discussed.