High-bandwidth nonreciprocal optical isolator based on a cascaded chiral cavity magnonic system

Cavity magnonic systems has been regarded as an ideal platform for various quantum technological applications. In this work, we propose a high-bandwidth optical isolator based on the cascading of chiral cavity magnonic systems, where each system consists of a torus-shaped microwave cavity and a YIG sphere inside. Utilizing chiral cavity-magnon coupling, the input signal in the given transmission direction along the waveguide can be fully transmitted, while the signal in the reverse direction is effectively isolated. Compared with the single-cavity setup, our optical isolator can significantly increase the effective bandwidth, enabling a nonreciprocal optical transmission with a high degree of isolation.