Enhancement and flexible control of slow light in a magnon–photon coupling system with N cavities

We theoretically analyze the transmission characteristics of a magnon–photon coupling system with N cascaded microwave cavities. The influences of the magnon–photon coupling strength and cavity number on the transmission characteristics are the main focus of this research. With an increase in the cascaded cavity number, the slow light effect should be greatly enhanced. By changing the cavity lengths slightly in a staggered way, the group delay could be increased by an order of magnitude with a well guaranteed transmission amplitude. Group delay should be flexibly controlled because of the existence of magnon and the conversion of fast and slow light can be realized. Moreover, by properly adjusting the cavity length, we can control the frequency shifting of the output slow light and narrow the bandwidth of the output slow light, which can aid in the design of high-quality light-storage devices. We believe the results will have applications in the all-optical communications network.