Interferometric near-field optical microscopy achieving a resolution o
f 10 angstroms is demonstrated,The scattered electric field variation
caused by a vibrating probe tip in close proximity to a sample surface
is measured by encoding it as a modulation in the optical phase of on
e arm of an interferometer. Unlike in regular near-field optical micro
scopes, where the contrast results from a weak source (or aperture) di
pole interacting with the polarizability of the sample, the present fo
rm of imaging relies on a fundamentally different contrast mechanism:
sensing the dipole-dipole coupling of two externally driven dipoles (t
he tip and sample dipoles) as their spacing is modulated.