Published in American Journal of Physics, Volume 72, Issue 9, September 1, 2004, pages 1195-1201.
Copyright © 2004 American Association of Physics Teachers. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Association of Physics Teachers. The following article appeared in American Journal of Physics and may be found at http://dx.doi.org/10.1119/1.1767102.
NOTE: At the time of publication, the author Glen Gillen was not yet affiliated with Cal Poly.
We discuss the origins and regions of validity of various near-field diffraction models. The complete Rayleigh–Sommerfeld model is found to accurately represent intensity distributions for axial distances up to and including the location of the aperture, a region where commonly used models fail. We show that near-field diffraction theory can be applied to the refraction of light at an interface between two different media yielding results that demonstrate the validity of Snell’s law in the presence of diffraction. Calculations using near-field diffraction and Fourier optics are compared to experimentally measured intensity distributions