An analytic formula for the light field amplitude (and therefore also intensity) behind a circular aperture illuminated by spherical or plane waves in the Fresnel limit is given, and the essential difference between Fresnel diffraction and Fraunhofer diffraction is discussed.
© 1998 Optical Society of America
Peng Wang, Yuguang Xu, Wei Wang, and Zhijian Wang, "Analytic expression for Fresnel diffraction," J. Opt. Soc. Am. A 15, 684-688 (1998)