Investigation on the physical mechanism of magnetic plasmons polaritons

Magnetic plasmons polaritons (MPP) mode has attracted a lot of attentions for the explanation of the interesting spectral features of a series of well-known systems of the metal/insulator/metal (MIM) structure with periodic patterns. In this paper, the resonance frequencies in the range from 75 to 750 THz predicted by the dispersion relation of MIM system are compared with those predicted by the equivalent LC circuit model to explore the physical mechanism of the excited resonance inside MIM structures at some frequencies. The spectral properties are simulated by the rigorous coupled-wave analysis (RCWA) method to verify the results predicted by means of the dispersion relation. The effects of the geometric parameters on the resonance phenomenon are investigated. It is found that the changes of resonance frequencies with geometric parameters predicted by the dispersion relation exhibit similar tendencies as those predicted by the equivalent LC circuit model. The spectral properties of unsymmetrical structures with different feature dimensions are utilized to further explain the physical mechanism of resonant phenomena inside MIM structures. The investigation indicates that MPP is in nature induced by the coupling of internal SPPs at the metal/insulator interfaces.

► Dispersion features of MIM structures can be predicted by the equivalent LC circuit model. ► Magnetic plasmons polaritons is induced by the coupling of internal surface plasmons polaritons at the metal/insulator interfaces. ► Structured parameters of metal/insulator/metal structures alter the behavior of MPPs and i-SPPs.