Nanocomposite material with the unit refractive index

Optical properties of a composite medium comprised of metallic nanospheres located at the sites of a three-dimensional lattice and embedded into a dielectric matrix are considered. It is shown that for a certain ratio of the dielectric constants, the refractive index of the composite medium may be equal to unity. A method taking into account the delay effects during interaction of nanospheres with radiation has been developed to describe the optical properties of the composite medium. It is shown that in the limit when the distances between nanospheres are negligibly small compared to the wavelength, the results coincide with the results of the Maxwell–Garnett theory.