Design of Super-Resolving Toraldo Pupils for Radio Astronomical Applications

Abstract

More than half a century ago, in 1952, Giuliano Toraldo di Francia suggested that the resolving power of an optical instrument could be improved using a filter consisting of finite-width concentric coronae of different amplitude and phase transmittance, now known as Toraldo Pupils (TPs). The concept of “super-resolution” was born, and in the cur- rent literature it is generally associated with various meth- ods for improving the angular resolution of an optical imag- ing system beyond the classical diffraction limit. In the mi- crowave range, the first successful laboratory test of TPs was performed in 2003. These first results suggested that TPs could represent a viable approach to achieve super- resolution in Radio Astronomy. We have therefore started a project devoted to an exhaustive study of TPs and how they could be implemented on a radio telescope. In this work we present a summary of the status of this project, and then we describe a preliminary design to implement a TP system on a 32-m radio telescope.