We have discussed the effective optical properties of Ag-PbSe plasmonic nanocomposites with different filling fraction in a broad frequency range at terahertz frequencies. The structures are composites of two different kinds of nanospheres, one made from chalcogenide dielectric materials PbSe and the other from a of Ag metal. In this paper, a theoretical approach is proposed to calculate an effective dielectric peroperties of Ag metallic nanospheres, randomly distributed and embedded in a uniform PbSe chalcogenide medium. The effective optical properties of the embedded particles is considered as well as surface plasmon resonance (SPR) of the Ag metal nanoparticles. It is found that the value of the effective dielectric properties decreases as a result the resonance wavelength shifts to shorter wavelengths.
