Pupils with Super Resolution

In 1952 Toraldo di Francia [Il Nuovo Cimento (Suppl.) 9 (1952) 426] proposed an intriguing concept to increase the optical resolving power. As a consequence, this theory could seem in contradiction with Heisenberg's uncertainty principle. In this Letter we report on the results of a microwave investigation which demonstrate the rightness of such theoretical predictions. Their interpretation, in relation to the uncertainty principle, is then discussed.