On the Phase Distributions in Images and Fraunhofer Diffraction Patterns Produced by a Thin, Non-aberrant Lens Illuminated by a Monochromatic Point Source of Light

The paraxial approximation is used to show that the phase distribution in the image plane for an object which itself introduces no phase distortions is that which would be obtained from a monochromatic point source placed in the Fraunhofer diffraction plane and vice versa. The idea of image formation as amplitude modulation of a carrier is suggested.