Coherent Asymmetric Absorber

Coherent illumination allows additional flexibility over metasurface functionalities, with coherent perfect absorbers as one typical example. However, most of coherent metasurface devices are based on spatially uniform metasurfaces that offer a limited control over scattered waves. In this talk, we present an idea of coherent asymmetric absorbers with periodic surface impedances. The proposed metasurface can function as a perfect retroreflector for coherent incidences from one side and as a perfect absorber for incidences from the other side.