Tunable coupling of mechanical vibration in GaAs micro-resonators

Control of the vibrational coupling in two mechanically coupled GaAs micro-resonators is demonstrated. The coupling efficiency depends on the eigenfrequency difference between the resonators. While the fabrication results in the eigenfrequency difference of ∼1% due to the patterning error, frequency modulation by the laser irradiation via the photothermal effect can compensate for the initial difference and realize perfect tuning. The two coupled vibrational modes exhibit the avoided crossing with the adjustment of the laser power, indicating the tunable coupling in the micromechanical system.