Strain coupling of a single exciton to a nano-optomechanical resonator

Abstract

We demonstrate the coupling of a semiconductor quantum dot (QD) to an optomechanical cavity, mediated by the strain of a nano-mechanical mode. The device comprises an optomechanical photonic crystal nanobeam in GaAs with embedded In(Ga)As QDs. The flexural mechanical mode of the device can be optically driven exploiting the large optomechanical coupling rate of the cavity. The vibrations generate a time-modulated strain field that shifts the quantum dot transition energy. We observe that optical driving of the mechanical mode induces a shift in an excitonic line corresponding to an estimated vacuum strain coupling rate of 214 kHz. Our approach represents an important step towards the use of phonons to couple different on-chip quantum systems.