Mirror symmetric nonreciprocity and circular transmission in cavity magnonics

We investigated the magnon–photon coupling in a threefold symmetry open cavity magnonic system, which leads to the mirror symmetric nonreciprocity and circular transmission. The strengths of the transmission coefficient in the anti-crossing area of the photon–magnon couplings are fully asymmetric. The results reveal the chiral selected circular transmission characteristic and the mirror symmetric nonreciprocity of the microwave transmission in the designed system. These effects can be understood with the chiral phase difference in the magnon–photon coupling, which lead to the circular microwave transmission. This scheme might be used as a circulator type non-reciprocal device in the cavity quantum electrodynamic systems.