Taming the Electromagnetic Boundaries via Metasurfaces: From Theory and Fabrication to Functional Devices

Figure 19

(a) Schematic of the coherent perfect absorber. (b) Absorption as a function of the frequency and the thickness of the doped silicon film. (c) Coherent absorption of a 450 nm thick doped silicon film. Red and green solid lines show the absorption for equal to 500 and 505.56 μm, respectively. (d) Coherent absorption of 17 nm thick tungsten for symmetrical and antisymmetrical inputs. (e) Schematic of plasmon hybridization and the effective medium description. For the symmetrical (antisymmetrical) resonance, the external -fields (-fields) should be parallel. (f) Coherent absorption of antisymmetrical inputs for TE polarization at oblique incidences. The inset of (f) illustrates the configuration of two coherent divergent beams with antisymmetrical phase distribution, where is the divergent angle. Figures are reproduced from [38, 123]. (g)–(i) Proposed applications of metasurface CPA in signal processing. Figures are reproduced from [124].

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