Three-dimensional self-assembly of metal nanoparticles: Possible photonic crystal with a complete gap below the plasma frequency

We study theoretically the optical properties of a three-dimensional self-assembly of spherical-metal nanoparticles. Our band-structure calculations show that photonic band gaps in near infrared and optical frequencies can be realized in a fcc lattice of metal particles with radii of approximately 160 nm. When absorption is taken into account. we found that the gap is preserved in good metals like silver. The metal nanoparticles can be replaced by dielectric spheres coated with a layer of good metal.