Magnon-induced absorption via quantum interference.

We propose a scheme to generate magnon-induced absorption (MIA) in a two-cavity magnonics system. By placing an yttrium iron garnet (YIG) sphere into one of two coupled microwave cavities, three different interference pathways are established by the photon coupling and magnon-photon coupling, leading to the conversion from suppression to enhancement on resonance under proper conditions. Most interestingly, the analytical results of the probe absorption are solved based on bright and dark modes in a dressed-state picture, which can be used to explain the position, width, and height of the absorption peaks accurately. Furthermore, we investigate the noise spectral density (NSD) of the microwave cavity and find out the similar MIA phenomena, which may provide a feasible way to remotely detect a magnon with an optical method.