Far-field and near-field analysis of light reflected from a photonic crystal

Multiple-scattering calculations of a plane wave reflected from a photonic crystal are presented under the assumption that the incident wavelength is larger than the size of the dielectric elements that constitute the crystal. After decomposing the reflected wave into its propagating and evanescent modes, we find that both the lattice constant and the size of the dielectric elements can be derived from the propagating modes but only the former quantity can be reliably obtained from the evanescent modes, implying that an examination of the waves in the far-field region alone yields practically most of the information about the crystal under the present assumption. One method to measure the size of the dielectric elements in the far-field region is also proposed.