Optical band structure and near-field intensity of a periodically arrayed monolayer of dielectric spheres on dielectric substrate of finite thickness

We examined numerically the effect of the finite thickness substrate on the optical properties of a two-dimensional periodic dielectric sphere. The photonic band dispersion is obtained from the transmission spectra for general oblique incidence. These results are in good agreement with experimental ones. Transmission spectra and the band dispersion are found to be significantly modified from those without substrate. This change is well explained by the anticrossing of eigenstates of the monolayer spheres and those bounded within the substrate. The characteristic feature of near-field intensity is investigated in detail when the eigenstates of the system are excited by the incident light. It is shown that the near-field intensity gives important information to figure out the origin of eigenstates. In addition, the shape of intensity distribution is analyzed by using the amplitudes of diffracted lights.