PHOTONIC BAND STRUCTURES OF OPTICALLY ANISOTROPIC PERIODIC ARRAYS

We use a plane-wave expansion to calculate the photonic band structure s of anisotropic dielectric composites. The composites consist of a pe riodic array of anisotropic dielectric spheres embedded in air. Calcul ations are carried out for spheres that are optically uniaxial or biax ial, Faraday active, or naturally optically active. Anisotropy in the sphere dielectric function is found to split degenerate bands and to n arrow or even close band gaps, analogous to Stark or Zeeman splitting in conventional band structures. At long wavelengths, the lowest bands are well described by effective indices of refraction, which are in f airly good agreement with an anisotropic Maxwell-Garnett approximation .