Broadband absorption in mid-infrared metamaterial absorbers with multiple dielectric layers

We have designed and fabricated broadband metamaterial absorbers working in the mid-infrared regime by employing the multilayered metal-dielectric-metal resonant stacks. Magnetic resonance is excited in each resonant stack, and the absorption peak wavelength is tuned by the dielectric constant of the dielectric layer. By stacking several resonant stacks with different dielectric layers, the absorption bandwidth can be effectively broadened through the hybridization of magnetic resonances in all resonant stacks. The presented design approach is an effective complement for constructing broadband metamaterial absorbers, and also meaningful in the design of other photonic devices.