Nanometric resolution with far-field optical profilometry.

We show experimentally that a resolution far beyond that of conventional far-field optical profilometers can be reached with optical diffraction tomography. This result is obtained in the presence of multiple scattering when using an adapted inverse scattering algorithm for profile reconstruction. This new profilometry technique, whose resolution can be compared to that of atomic microscopes, also gives access to the permittivity of the surface.