Phase change in a diffracted wave: a Cornu spiral perspective
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Updated: Jun 8, 2026

Fourier-Based Diffraction Analysis of Live Caenorhabditis elegans
Published on: September 13, 2017
1Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, A.P. 1-1010, Santiago de Querétaro 76000, México. r.avila@crya.unam.mx
Abstract:
A simple evaluation of the phase change in a diffracted wave, in terms of the Cornu spiral, is presented to complement the well-known intensity change, which is routinely obtained for this elegant graphical construction of the Fresnel integrals. This is, to the best of our knowledge, the first presentation of this evaluation. It is shown that the phase of a wave diffracted by a slit is equal to the slope of the line tangent to the Cornu spiral, shifted by π/4.
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