The Stratton–Chu theory of electromagnetic (EM) scattering is used to develop a Kirchhoff formalism of the diffraction of EM waves by an aperture. The theory is applied to the study of the diffraction of a polarized EM wave by small-Fresnel-number systems. It is demonstrated through sample numerical calculations that the vectorial aspects of the EM waves are important, especially for fields in the microwave regime. The focal shift is then calculated with the vectorial aspects taken into account.
© 1994 Optical Society of America
Original Manuscript: January 21, 1993
Revised Manuscript: August 16, 1993
Manuscript Accepted: August 17, 1993
Published: February 1, 1994
Wenyue Hsu and Richard Barakat, "Stratton–Chu vectorial diffraction of electromagnetic fields by apertures with application to small-Fresnel-number systems," J. Opt. Soc. Am. A 11, 623-629 (1994)