Multipolar localized resonances for multi-band metamaterial perfect absorbers

A metamaterial structure, comprising of metallic circular micro-discs (gold or aluminum) separated from a metallic thin film by a dielectric zinc sulphide film, behaves as a multi-band perfect absorber at infra red wavelengths due to the excitation of multipole resonances. With micro-discs of 3.2 mu m diameter, the fabricated metamaterial absorber shows peak absorbance of over 90% in multiple selected bands spanning the 3-14 mu m wavelengths. Absorption bands corresponding to the different resonance modes have been measured and computational simulations show these resonances originate from the higher order multipolar resonances of the disk.