Nanoscale mechanical actuation and near-field read-out of photonic crystal molecules

We employed the contact forces induced by a near-field tip to tune and probe the optical resonances of a
mechanically compliant photonic crystal molecule. Here, the pressure induced by the near-field tip is exploited to control the spectral proprieties of the coupled cavities in an ultrawide spectral range, demonstrating a reversible mode shift of 37.5 nm. Besides, by monitoring the coupling strength variation due to the vertical nanodeformation of the dielectric structure, distinct tip sample interaction regimes have been unambiguously reconstructed with a nano-Newton sensitivity. These results demonstrate an optical method for mapping mechanical forces at the nanoscale with a lateral spatial resolution below 100 nm.