Optomechanical dark mode

Summary form only given. Thermal mechanical motion hinders the use of a mechanical system in applications such as quantum information processing. A straightforward, but technically challenging, approach to overcome the thermal motion is to cool the mechanical oscillator to its motional ground state. An alternative approach, as proposed recently, is to exploit the use of a mechanically-dark mode, which is a special coherent superposition of two optical modes [1, 2]. The cancellation in the mechanical coupling induced by the superposition decouples the dark mode from the mechanical oscillator. The formation of the dark mode, however, also induces a conversion of the optical field from one optical mode to the other. This type of mechanically-mediated coupling is immune to thermal mechanical motion, providing a promising mechanism for interfacing hybrid quantum systems. Here, we report the experimental demonstration of such a dark mode by coupling two optical modes in a silica resonator to one of its mechanical breathing modes in the regime of weak optomechanical coupling [3].