The superresolving filter design of Toraldo di Francia [Atti. Fond. Giorgio Ronchi <b>7</b>, 366 (1952)], which consists of an array of concentric annuli of finite width, is studied. Such a filter compares favorably with other superresolving filter designs while being considerably more simple to fabricate. In particular, for given input energy, the intensity at the focal point is usually greater than for optimized filter designs. The manufacturing tolerances of such a filter are discussed.
© 1982 Optical Society of AmericaPDF Article