Effective non-retarded method as a tool for the design of tunable   nanoparticle composite absorbers
  We investigate the capabilities of the effective non-retarded method (ENR) to explore and design nanoparticles composites with specific optical properties. We consider a composite material comprising periodically distributed metallic spheres in a dielectric host matrix. The effective macroscopic dielectric function of the composite medium is obtained by means of the ENR and is used to calculate the electromagnetic response of a slab made of such an inhomogeneous material. This response is compared with that obtained using the Korringa-Kohn-Rostoker wave calculation method (KKR). We analyze the optical properties for different filling fractions, especially in the vicinity of the resonance frequencies of the macroscopic dielectric function. We show that appropriately choosing the parameters of the composite it is possible to achieve a tunable absorber film. The ENR results to be a versatile tool for the design of nanoparticle composite materials with specific properties. 
Guillermo Ortiz, Marina Inchaussandague, Diana Skigin, Ricardo Depine   and Luis Moch\'an
physics.optics