Nonreciprocal Transparency in Asymmetric Gyrotropic Trimers

We demonstrate theoretically an extreme scattering nonreciprocity, namely nonreciprocal transparency, in an asymmetric aggregate of deep-subwavelength gyrotropic trimer rods. By examining the asymmetric characteristics indicated in the differential extinction efficiency spectra, we explicitly reveal the underlying mechanism of such pronounced scattering nonreciprocity, arising from the asymmetrical magnetoelectric cross interactions besides the simultaneous excitations of the rotating magnetic dipole and electric dipole at each rod. Further, both far-field and near-field distributions are also investigated to validate our finding through full-wave numerical simulations. It may shed new light on the field of optics and photonics related to the nonreciprocal scattering on particle clusters.