Photonic-doped Zero-index Media as Coherent Perfect Absorbers

Defects usually play an important role in modifying the properties of electronic or electromagnetic materials. Very recently, photonic doping in zero-index media has been proposed by Nader Engheta's group (Science 355, 1058 (2017)), endowing the zero-index media with unprecedented properties of electromagnetic wave manipulation. Here, we theoretically and experimentally demonstrate the realization of coherent perfect absorption by using photonic doping of zero-index media with absorptive defects. Interestingly, such coherent perfect absorption is independent of the size and shape of this photonic-doped zero-index medium absorber, as well as the position of the doping defects. Moreover, such a doping scheme also enables novel ways to control absorption, such as multiple channels and multiple doping defects, etc.