Broadband and Wide-Angle Nonreciprocity with a Nonhermitian Metamaterial

摘要

We theoretically demonstrate a non-hermitian metamaterial exhibitingbroadband and wide-angle nonreciprocity. The metamaterial consists of planarmetal-dielectric layers with a Parity-Time (PT) symmetric distrubtion of lossand gain. With increasing loss and gain, the bandstructure and bandgap arestrongly modified; further, the PT potential leads to distinct internal fielddistributions when illuminated from different sides. Including nonlinearitiesarising from natural loss and gain saturation leads to nonreciprocaltransmission in the visible over a 50 nm wavelength and 60$^{\circ}$ degreeangular range.