Optical Absorption of a Composite Based on Bimetallic Nanoparticles. Classical Approach

The absorption of electromagnetic radiation by a composite based on bimetallic nanoparticles with a “core–shell” type of structure has been analyzed using the Maxwell–Garnett theory. Expressions have been obtained for the real and imaginary parts of the dielectric function of a two-layered particle in the limiting cases of “thick” and “thin” shells. It has been established that the presence of two metals in the composition of the inclusions leads to a splitting of the maxima and minima in the frequency dependences of the dielectric function and of the coefficient of absorption of the nanocomposite. The frequency dependences of the real and imaginary parts of the dielectric function and of the coefficient of absorption of the composite with bimetallic nanoparticles of different metals have been calculated. An essential influence of both the geometric characteristics of the particles-inclusions and of their composition on the optical properties of the composite has been revealed.