Optical Tuning of Coupled Micromechanical Resonators

Frequency tuning of two mechanically coupled microresonators by laser irradiation is demonstrated. The eigenfrequency of a doubly clamped GaAs beam shifts downward in proportion to laser power due to optically induced thermal stress, which modifies the spring constant of the resonator. This frequency tuning enables the control of the coupling efficiency and thus the realization of perfect coupling between the micromechanical resonators, i.e., purely symmetric and anti-symmetric coupled vibration. This optical tuning is a valuable method for the study of physics in coupled resonators as well as for expanding the applications of micromechanical resonators for sensors, filters, and logics.