Wide-Angle Dual-Band Absorber Based on Nanowire-Hyperbolic Medium

We proposed a dual-band absorber in the visible regime by using nanowire-hyperbolic medium, which is composed of an array of subwavelength-sized hybrid nanowires immersed in dielectric matrix, as a top layer, silicon dioxide as a middle layer, and gold as a bottom layer. Each nanowire is made by core-shell structure, which has silicon as a core and gold as a shell. We found that the dual-band absorption originated from impedance matching between incident medium impedance and input impedance of the proposed absorber at first- and second-order resonant modes. Furthermore, the absorbance can be controlled by adding or reducing filling factor of hyperbolic medium layer. In addition, the absorption performance of the absorber retains well in wide angles. This dual-band absorber is a good candidate for potential applications such as thermal radiation tailoring and sensitive detection.