Surface plasmon polaritons and its coupling with cavity mode in the system of dielectric spherical shells periodically mounted in a metal substrate

Abstract

We investigate the surface plasmon polaritons and its coupling with other electromagnetic modes by observing the absorption spectrum on a system of dielectric spherical shells periodically mounted in a metal substrate. We found that there exist two resonance frequencies in the system corresponding to surface plasmon polaritons mode and cavity mode. At these frequencies, we can find related peaks i n absorbance. Since the surface plasmon polaritons cannot couple with the incide nt plane wave directly and both couplings of the cavity mode with the incident w ave and the surface plasmon polaritons are also weak, so the strength of absorpt ion peaks are generally very limited. However, we can adjust some parameters in the system to make the surface plasmon polaritons and the cavity mode with almos t the same frequency. In this case, the coupling can be dramatically enhanced, a nd we can observe very strong peaks in absorbance. The relationships of resonanc e absorption with some physical and geometrical parameters are discussed in deta il.