Roberto Coïsson

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The spatial coherence properties of a monochromatic component of synchrotron radiation from an insertion device in the Fraunhofer limit are analyzed in the general case when the coherence distance is comparable with the beam width, expressing them by simple products and convolutions of Fourier transforms and autocorrelations on the single-electron field(More)
Gauss-Schell light sources are considered as models for synchrotron radiation. These sources can be viewed as random superpositions of coherent Gaussian beams. The relationships of the various widths that can be defined for the description of intensity and coherence, as related to the widths of the electron beam and the single-electron radiation(More)
Using two small flat mirrors under grazing incidence, we have produced interference patterns from partially coherent x-ray beams at the European Synchrotron Radiation Facility. By piezoelectrically orienting one mirror around the horizontal plane, both the vertical and horizontal transverse coherence distances of the radiation have been measured. The(More)
With a small double-mirror setup, we used grazing-x-ray interferometry to study nanometric steps. These one-dimensional steps were microfabricated upon the surface of one of the two mirrors; the other mirror provided the reference wave. Two geometries were studied. In the longitudinal case in which the x rays are parallel to the step edges, it is(More)
Some problems relative to the use of three lasers beams of different colours and colour image detectors for real-time electronic speckle interferometry (ESPI) are discussed. A simple ESPI setup is proposed, allowing non-contact real time mapping of displacements and strain of a surface, simultaneously in the three directions.
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