Coherent Perfect Absorption via Photonic Doping of Zero‐Index Media

Abstract

AbstractCoherent perfect absorption, as time‐reversed lasing, is achieved via appropriate interference of waves in absorbers and provides attractive opportunities for flexible control of light scattering and absorption. Here, the authors theoretically and experimentally demonstrate the realization of coherent perfect absorption by using photonic doping of zero‐index media with absorptive defects. Interestingly, the coherent perfect absorption is independent of the size and shape of this “doped” zero‐index medium absorber, as well as the position of the doping defects. This exceptional absorption property can be well explained via the photonic doping theory for zero‐index media. Moreover, the authors demonstrate that the doping scheme also enables novel ways to control absorption, such as multiple channels and multiple doping defects, etc. This work proposes a unique doping approach for advanced coherent perfect absorption with versatile control functionalities.