- Conference date: 21–26 October 2007
- Location: Campinas, São Paulo (Brazil)
The spreading properties of the Fraunhofer diffraction patterns of optical fields in any state of spatial coherence along the z‐axis are both theoretically and numerically analysed using the so called spatial coherence wavelets. The numerical analysis is performed by studying the one‐dimensional diffraction pattern produced when a single slit is uniformly illuminated with a Gaussian Schell‐model field. The diffraction pattern is understood as the result of contributions provided by spatial coherence wavelets coming from two different regions within the aperture, called the inner circle and the truncation crown respectively. It is shown that shape‐invariant spots with minimum spreading along the z‐axis can be obtained by properly modulating the spatial coherence properties along the truncation crown. Those spots can be regarded as finger prints of the spatially partially coherent optical field, in the sense that they only depend on the spatial coherence properties and not on the shape of the aperture itself. Numerical evidence shows that eliminating the contributions coming from the mentioned crown reduces the spreading to its minimum value for a given z distance. Therefore, the suppression of the contributions coming from the crown also suggests a way to eliminate spreading. The experimental implementation of this principle is a subject of research at the present.
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