  We theoretically demonstrate a non-hermitian metamaterial exhibiting
broadband and wide-angle nonreciprocity. The metamaterial consists of planar
metal-dielectric layers with a Parity-Time (PT) symmetric distrubtion of loss
and gain. With increasing loss and gain, the bandstructure and bandgap are
strongly modified; further, the PT potential leads to distinct internal field
distributions when illuminated from different sides. Including nonlinearities
arising from natural loss and gain saturation leads to nonreciprocal
transmission in the visible over a 50 nm wavelength and 60$^{\circ}$ degree
angular range.
