Optical excitation of multiple standing spin modes in three-dimensional optomagnonic nanocavities

We report the experimental observation of multiple standing spin modes in a three-dimensional (3D) optomagnonic nanocavity formed by a nanometer-sized iron-garnet nanocylinder. We show that launching of the standing spin modes is achieved due to a high confinement of the optically generated effective magnetic field caused by the localized optical resonance. Quantization and spin-wave mode inhomogeneity are achieved in each of the three spatial dimensions. The presented approach opens horizons for 3D optomagnonics by combining nanophotonic and magnonic functionalities within a single nanocavity.