Optical properties of metal-chalcogenide dielectric XSe–Ag (X = Pb or Zn) nanostructured composite

We have discussed the effective optical properties of XSe–Ag (X = Pb or Zn) plasmonic metal-chalcogenide dielectric nanostructured composites in a broad frequency range at high frequencies. The structures are composites of two different kinds of nanospheres, one made from metallic Ag nanospheres, randomly distributed and embedded in a uniform chalcogenide dielectric medium. The effective optical properties for different volume fractions of the embedded particles is considered as well as surface plasmon resonance (SPR) of the Ag nanoparticles. It is found that the value of the effective dielectric permittivity decreases with an increasing filling fraction and as a result the resonance wavelength shifts to shorter wavelengths. The Fano resonance has been also found in these plasmonic nanostructured composites.