Biomedical subjects

Franco Gori

Publications and source records attributed to Franco Gori.

6 recordsLinked to original sources

PubMed2006

Phase and amplitude retrieval in ghost diffraction from field-correlation measurements.

We report the results of experiments about the inversion of ghost diffraction with pseudothermal light. A complete retrieval of the complex transmission function of planar transparencies, illuminated by spatially incoherent, quasimonochromatic light, is achieved. This is obtained by measuring the field (instead of the intensity) correlation function. In particular, the determination of the phase of the correlation function is made particularly easy and robust by the use of a suitably modified Young interferometer. The presented results refer to the cases of a clear slit and a phase step.

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PubMed2006

Vector mode analysis of a young interferometer.

It is proved that, when the vector modal theory of coherence is applied to a pair of fixed points, exact results are obtained for the mode structure. In particular, it is shown that the field radiated by the pinholes of a Young interferometer can always be represented by the incoherent superposition of no more than four perfectly correlated and polarized modes. The role of such modes is illustrated through a simple example.

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PubMed2006

Effects of coherence on the degree of polarization in a young interference pattern.

Recent predictions concerning the relationship between the degree of polarization at a typical point of a Young interference pattern and the degree of coherence of the electromagnetic field at the pinholes are tested by a simple experiment. In particular, it is shown that light that is completely unpolarized at the pinholes can become partially polarized across the fringe pattern.

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PubMed2005

Far-zone approximation for partially coherent sources.

A general condition is derived for the distance beyond which the far-zone approximation can be used in studying propagation of light from a partially coherent source. The distance steadily increases as a function of the coherence radius across the source, reaching the usual value in the coherent limit.

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PubMed2003

Coherent-mode decomposition of partially polarized, partially coherent sources.

It is shown that any partially polarized, partially coherent source can be expressed in terms of a suitable superposition of transverse coherent modes with orthogonal polarization states. Such modes are determined through the solution of a system of two coupled integral equations. An example, for which the modal decomposition is obtained in closed form in terms of fully linearly polarized Hermite Gaussian modes, is given.

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PubMed2003

Evaluation of the spatial coherence of a light beam through transverse intensity measurements.

The problem of recovering the coherence features of a partially coherent quasi-monochromatic scalar optical source, starting solely from intensity measurements on the emitted beam, is addressed in the most general way, under the paraxial approximation. In particular, it is shown that on expanding the beam emitted by the source as a bundle of partially correlated Hermite-Gaussian beams, the correlation coefficients can be recovered, in principle, simply by performing scalar products between transverse intensity distributions and suitably defined functions.

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