Photonic-band-structure effects for low-index-contrast two-dimensional lattices in the near-infrared

We demonstrate that two-dimensional periodic dielectric structures with low index contrast give rise to remarkable photonic band-structure effects. Our structures consist of triangular arrays of glass cylinders embedded in a matrix composed of a different glass, having center-to-center nearest-neighbor separations from 1.08 {μ}m to 0.54 {μ}m. The indices of refraction of the two glasses differ by less than 0.02 in the relevant spectral region. The attenuation features corresponding to the boundaries of the first Brillouin zone appear in the near-infrared, at photon energies between 0.4 eV and 0.9 eV.