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 μm diameter, the fabricated metamaterial absorber shows peak absorbance of over 90% in multiple selected bands spanning the 3–14 μm 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.