Stationary entanglement between light and microwave via ferromagnetic magnons

We show how to generate stationary entanglement between light and microwave in a hybrid opto-electro-magnonical system which mainly consists of a microwave cavity, a yttrium iron garnet (YIG) sphere and a nanofiber. The optical modes in nanofiber can evanescently coupled to whispering gallery modes, that are able to interact with magnon mode via spin-orbit interaction, in YIG sphere, while the microwave cavity photons and magnons are coupled through magnetic dipole interaction simultaneously. Under reasonable parameter regimes, pretty amount of entanglement can be generated, and it also shows persistence against temperature. Our work is expected to provide a new perspective for building more advanced and comprehensive quantum networks along with magnons for fast-developing quantum technology and for studying the macroscopic quantum phenomena.