Experimental generation of circulating cavity magnon polaritons

Abstract

We experimentally realize circularly polarised unidirectional cavity magnon polaritons in a torus-shaped microwave cavity loaded by a small magnetic sphere. At special positions the clockwise and counterclockwise modes are circularly polarized, such that only one of them couples to the magnet, which breaks the mode degeneracy. We reveal the chiral nature of the spectral energy and angular momentum flow by observing and modelling non-reciprocities of the microwave scattering matrix.

7 pages, 7 figures