Singular beam microscopy.

Optical singularities are localized regions in a light field where one or more of the field parameters, such as phase or polarization, become singular with associated zero intensity. Singular beam microscopy exploits the fact that the strong variations of the optical field around the singularities are highly sensitive to changes in their neighborhood. As a consequence, analysis of the light field scattered from the object during a scanning process can yield useful information about the object features. We present a theoretical background, numerical simulations, and experimental results. Preliminary experiments have demonstrated a sensitivity of 20 nm in the position and size of simple objects, with theoretically estimated 1 nm capability under the assumption of a reasonable and conservative 30 dB signal to noise ratio.