Tuning Fano resonance by plasmonic core-shell nanostructure

The scattering property of core-shell subwavelength structure is analyzed. It is found that this structure could generate Fano resonance when its aspect ratio η approaches zero or one. The specific conditions of forming Fano resonance for η→0 and η→1 are derived. Based on these conditions, we propose to generate tunable Fano resonance using the nanostructure with dielectric-core and graphene-shell. The resonance wavelength can be tuned by changing the chemical potential of graphene. Besides, the structure made of anisotropic dielectric and plasmonic materials is also proposed to adjust the Fano resonance, which could adjust the resonance wavelength in wider spectrum than traditional core-shell structure.