  Classically coherent dynamics analogous to those of quantum two-level systems
are studied in the setting of force sensing. We demonstrate quantitative
control over the coupling between two orthogonal mechanical modes of a nanowire
cantilever, through measurement of avoided crossings as we deterministically
position the nanowire inside an electric field. Furthermore, we demonstrate
Rabi oscillations between the two mechanical modes in the strong coupling
regime. These results give prospects of implementing coherent two-mode control
techniques for force sensing signal enhancement.
