One-Way Extraordinary Optical Transmission and Nonreciprocal Spoof Plasmons

We introduce a concept of a nonreciprocal spoof surface plasmon: an electromagnetic wave supported by a structured conductor embedded in an asymmetric magneto-optical medium and exhibiting a nonreciprocal dispersion. It is demonstrated analytically and by first-principles electromagnetic simulations that, by breaking the time-reversal symmetry, nonreciprocal spoof surface plasmons enable a dramatic optical response: one-way extraordinary optical transmission.