Light reflectance in opal-based metal-dielectric photonic crystals

The light reflectance in 3-dimensional metal-dielectric photonic crystals assembled from polyelectrolyte-coated latex spheres infiltrated with gold nanoparticles prior or after opal crystallisation has been studied. Strong deviation of the optical reflectance of Au-opals from bare opals has been observed, including flattening of the diffraction resonance dispersion and topology dependence of surface plasmon bands. Depending on whether the infiltration was made before or after opal crystallisation, the plasmon reflectance shows different band central frequencies as well as band positioning as the function of angle. The strong alteration of shape of the reflectance spectrum has been demonstrated in the case of overlapping the diffraction and plasmon resonances.