Topological phonon transport in an optomechanical system

We report the observation of topological phonon transport within a multiscale optome-chanical crystal structure consisting of an array of over 800 cavity-optomechanical ele- ments. Using sensitive, spatially resolved optical read-out we detect thermal phonons in a 0.325 − 0.34 GHz band traveling along a topological edge channel, with substantial reduc- tion in backscattering. This represents an important step from the pioneering macroscopic mechanical systems work towards topological phononic systems at the nanoscale.