ABSTRACT
Opal-like structures, consisting of lattices of dielectric spheres, are the most commonly studied example of three-dimensional (3D) photonic crystals (PCs).1 Since they were proposed as new materials to mold the ƒow of light, they have become an important area of research because of their technological potential and fundamental interest.2 Among all fabrication techniques developed up to date to prepare opaline PCs, those based on evaporation-induced self-assembly (EISA) are some of the most frequently used and thoroughly analyzed.3 The advent and subsequent improvement of fabrication techniques that take advantage of self-organizing properties of dielectric spheres in the micrometer scale have permitted to obtain solid colloidal crystals that exhibit PC properties,4,5 whose optical response has been studied in depth in the low-energy range, where the lattice parameter is smaller than the incident wavelength.6
