A metal-dielectric-metal structure with cross-shaped-hole array in metal thin films is studied for plasmonic multispectral filters, which covers visible to near-infrared wavelengths. Surface plasmons are induced from incident wave by a periodic array of nanostructures, then the localized surface plasmon polaritons oscillate in the cavity, which is formed by the two layers of metals through near-field excitation. The transmission spectrum of the metal-dielectric-metal structure with cross-shaped-hole array is investigated with the finite-difference time-domain method; our simulations show that the features of the hole, and the refractive index and the thickness of the dielectric layer all affect the optical spectral performance. This metal-dielectric-metal structure provides additional flexibility in tuning transmission spectrum due to its Fabry-Perot cavity property. Our study shows that it is possible to obtain desired multispectral filters by programming the refractive index and thickness of the dielectric layer, and these parameters of the metallic structures.
Keywords: Surface Plasmon; Metallic Nanostructures; Multispectral Filters.