Design and Test of a Toraldo Pupil Optical Module for the Medicina Radio Telescope

Toraldo Pupils (TPs) can improve the angular resolving power of an optical instrument beyond the classical diffraction limit (hence the term super-resolution) using a filter consisting of finite-width concentric coronae with different amplitude and phase transmittance. The first successful laboratory test of TPs in 2003 suggested that these devices 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 design and laboratory tests of an optical module based on TPs that we plan to field-test on the Medicina 32-m radio telescope.