Realization of broadband coherent perfect absorption of spoof surface plasmon polaritons

In this work, we propose and demonstrate a scheme to realize broadband coherent perfect absorption of spoof surface plasmon polaritons (SPPs) using an ultrathin conductive film vertically placed on a plasmonic metasurface that supports spoof SPPs. When the conductive film possesses an appropriate sheet resistance, two incident coherent beams of spoof SPP waves can be simultaneously absorbed over a broad spectrum. By tuning the phase difference between the two incident beams from 0 to pi, the absorption can be gradually changed from near-100% to near-zero, as verified in full-wave simulations and microwave experiments. Our work extends the theory of coherent perfect absorption from propagating waves to spoof SPPs with a significant advantage of broad working bandwidth. Published under an exclusive license by AIP Publishing.

Automated summary

In this study, we propose and demonstrate a scheme to achieve broadband coherent perfect absorption of spoof surface plasmon polaritons using an ultrathin conductive film. By adjusting the sheet resistance of the conductive film and the phase difference between the incident beams, absorption can be achieved over a wide spectrum.