Nonreciprocity brings new features to ultimately thin absorbers

Single-layer arrays of electrically small bianisotropic particles tuned to perform as perfect absorbers (at normal incidence) are considered. It is shown that it is possible to design the layers so that they absorb power of incident waves from one side. Possible new functionalities due to nonreciprocal coupling in the array for the wave coming from opposite side, are studied. It is shown that by properly choosing the type of the magnetoelectric coupling in the particle and tuning its strength it becomes possible to realize layers which absorb waves coming from one side and act as ultimately thin isolators or twist polarizers from the other side.