Coupling between gap plasmon polariton and magnetic polariton in a metallic-dielectric multilayer structure.

The excitation of plasmons in a metallic nanostructure represents a feasible and practical approach for manipulating the propagation and absorption of light at the subwavelength scale. Of particular interest is the coupling between plasmons, which can be used to facilitate the spectral tunability and tailor the optical response of the structure. In this paper, we study the coupling between two highly localized plasmonic modes: gap plasmon polariton mode and magnetic polariton mode, supported by a metallic-dielectric multilayer structure. The strong coupling gives rise to the formation of hybrid plasmon modes and large mode splitting. These hybrid modes result in unique spectral-directional absorption characteristics in the structure. The findings hold promise in applications such as photonic and energy conversion systems as well as the design of plasmonic nanodevices.