Gaussian Schell-model sources: an example and some perspectives

In this paper we deal with the use of feedback systems to generate Gaussian Schell-model sources. Owing to the approximation of quasi-homogeneity of the beam and assuming slow transmittance variations of diffracting elements, the coherence-propagation equation can be simplifed and leads after several transits to a multiple-convolution product. According to the central-limit theorem and whatever the pupil functions are, this product reduces in general to a Gaussian distribution. This result is applied to imaging and lensless feedback systems.