Direction-Dependent Wave Transformations in Switched Artificial Moving Media

Time-invariant bi-anisotropic media have been broadly studied, revealing many interesting effects due to the presence of magnetoelectric coupling between the flux densities and fields. We expect that considering time-dependent coupling phenomena will open an alternative avenue for controlling waves and uncovering novel functionalities. In this talk, in particular, we contemplate nonstationary nondispersive artificial moving media and study wave propagation when the effective velocity parameter, as a nonreciprocal magnetoelectric coupling coefficient, vanishes abruptly in time. We show that such a temporal discontinuity results in directional effects for the energy transfer and frequency translation.