Strong magnetochiral dichroism in chiral/magnetic layered heterostructures

In this Letter, we propose a nonreciprocal heterostructure which combines magnetism and chirality in a simple, easy-to-fabricate design and exhibits at least two orders of magnitude larger magnetochiral dichroism, compared to other proposed metamaterials. This effect stems from the simultaneous lack of time-reversal and space-inversion symmetries and is enhanced by collective slow-photon modes originating from the strong bending of the photonic bands at the Brillouin zone boundaries. We investigate the optical properties of this bianisotropic multilayer heterostructure, consisting of consecutive bilayers of chiral and magnetic materials, embedded in air, and discuss the associated photonic band structure and transmission/absorption spectra obtained by means of full electrodynamic calculations.