Observation of Static Non-Reciprocity in an Optomechanical System

Non-reciprocal elements play an important role in the control of mechanical, electrical, and optical systems. One means of inducing non-reciprocity is provided by non-Hermitian systems, in which a system couples to its environment with gain and/or loss. We recently demonstrated non-reciprocal energy transfer between two vibrational modes in an optomechanical system by employing time-dependent operations via a control laser. Here we demonstrate non-reciprocal energy transfer in the same system, but using static control lasers. The non-reciprocity between the vibrational modes is shown to be more than 30dB.