The three-dimensional transfer function and phase space mappings

For paraxial wave-fields in two dimensions, it is known that the defocused OTF is given by a section through the ambiguity function. This is no longer true for high aperture fields. It is shown that there is a simple relation ship, even for high aperture fields, between the two-dimensional (one trans verse and one longitudinal) generalized OTF and the spectral correlation fu nction. The connection with the Wigner distribution function is also discus sed. The generalization to three-dimensional wavefields is also considered.