Tuning strain coupling between diamond oscillators and NV centers via interference of two mechanical modes

Strain mediated by mechanical motion provides a powerful resource for controlling solid-state qubits in hybrid quantum systems. Leveraging more than one mechanical mode enables extended control capabilities that are inaccessible with a single mode. In this work, we experimentally demonstrate multimode strain engineering in hybrid systems comprising nitrogen-vacancy (NV) centers in diamond coupled to the mechanical motion of diamond oscillators via strain. By simultaneously driving flexural and torsional modes in T- and U-shaped oscillators and tuning their relative phases and amplitudes, we selectively enhance or suppress longitudinal strain coupling. Numerical simulations further suggest the possibility of independently controlling both longitudinal and transverse strains using membrane-like oscillators that support nearly degenerate mechanical modes. This approach paves the way for advanced mechanical control in hybrid quantum systems through multimode engineering.