Title: Possible Realization of Directional Optical Waveguides in Photonic Crystals with Broken Time-Reversal Symmetry
Abstract: We show how, in principle, to construct analogs of quantum Hall edge states in "photonic crystals" made with nonreciprocal (Faraday-effect) media. These form "one-way waveguides" that allow electromagnetic energy to flow in one direction only.