Tunable multiband metasurfaces based on plasmonic core-shell nanoparticles

Metasurfaces, which can act as wavelength-selective surfaces with multiple passbands or stopbands, have numerous applications, including modulating electromagnetic radiation, and transmitarray or reflectarray antennas. In this paper, the feasibility of such metasurfaces, using plasmonic core-shell nanoparticles, has been studied. By analyzing the polarizability of such particles, it is shown that they are capable of possessing two plasmonic resonances that can be tuned to specific wavelengths by adjusting their design parameters and the constitutive media. In addition, a passband exists in between these two bands. The surface susceptibilities of the metasurface are determined using "sparse approximation formulas." Analytical scattering coefficients were compared and found to agree with numerical results obtained using full-wave simulation.