Nonmagnetic Linear Optical Nonreciprocity in Acoustically Driven Resonant Waveguide Gratings

Nonmagnetic nonreciprocal linear optical response is predicted for acoustically driven resonant waveguide gratings. In a narrow spectral range around the resonance the structure can be completely transparent for a light wave propagating in one direction and highly reflective in the opposite direction. As resonances are revealed in the zeroth diffraction order, the frequency of the transmitted/reflected waves is the same as the frequency of the incident wave, while resonantly enhanced guided mode field oscillates at the frequency shifted up or down due to acousto-optic coupling mediated by a traveling sound wave.