OPTICAL TRANSFER-FUNCTION DESIGN BY USE OF A PHASE-ONLY COHERENT TRANSFER-FUNCTION

The design of a desired optical transfer function (OTF) is a common op tical problem that has many possible applications. A well-known applic ation for the OTF design is beam shaping for incoherent illumination. However, other applications, such as optical signal processing, can al so be addressed with these systems. We derive a mathematical expressio n for an optimal phase-only filter that, when attached to an imaging l ens, provides an optimal approximation in the sense of the minimal mea n square error to the desired OTF function. Because of the fact that a phase-only filter is used, high efficiency is achieved. (C) 1997 Opti cal Society of America.