Multi-channel coherent perfect absorbers

The absorption efficiency of a coherent perfect absorber usually depends on the phase coherence of the incident waves on the surfaces. Here, we present a scheme to create a multi-channel coherent perfect absorber in which the constraint of phase coherence is loosened. The scheme has a multi-layer structure such that incident waves in different channels with different angular momenta can be simultaneously and perfectly absorbed. This absorber is robust in achieving high absorption efficiency even if the incident waves become incoherent and possess random wave fronts. Our work demonstrates a unique approach to designing highly efficient metamaterial absorbers. Copyright (C) EPLA, 2016