Customizing twisted Schell-model beams

Abstract

Since the celebrated twist phase was proposed by Simon and Mukunda, despite the tremendous progress made in theory over the past decades, developing a simple and flexible experimental method to customize this novel phase has long been a tricky challenge. In this Letter, we demonstrate a general experimental method for generating twisted Schell-model beams by implementing the continuous coherent beam integral function in a discrete form. Experimental results based on rigorous Laguerre–Gauss modes superposition are also demonstrated, indicating that our method is more convenient and of higher quality. The twist factor is also measured using the rotation characteristics during propagation, and the results agree well with the theoretical prediction. The method could serve as a general way for customizing bona fide twisted cross-spectral densities while facilitating certain applications.

A New Type of Shape-Invariant Beams with Structured Coherence: Laguerre-Christoffel-Darboux Beams

“…The three values of r 2 are chosen as follows: the first one corresponds to a point close to the inner border of the intensity donut; the second one is in the central part of the donut; and the third one is near the outer border of the donut. For any of these sources, complete correlation is observed for any pair of points located on the same circle concentric with the source center, as it was expected from Equation (41). Furthermore, within the region where the intensity is not negligible, the absolute value of the degree of coherence shows N minima, where it vanishes, meaning that there could be complete incoherence between points belonging to different circles.…”

“…It is seen that the absolute value of γ Nm depends only on the radial distances of the considered points from the source center, so that the source exhibits perfect coherence along any annulus that is concentric to the source center, i.e., |γ Nm (r, ϕ 1 ; r, ϕ 2 )| = 1 (41) for any choice of m, ϕ 1 and ϕ 2 . In this sense, the sources present circular coherence [49,50].…”

“…Therefore, no twist can be present in a perfectly coherent source [26][27][28][29][30]. Research on partially coherent sources presenting a twist is still very active [31][32][33][34][35][36][37][38][39][40][41][42].…”

“…Sources of this class could be experimentally generated following the procedures described in Refs. [41,46].…”

Evaluation of Twisted Gaussian Schell Model beams produced with phase randomized coherent fields

“…Despite the extensive theoretical progress in studies involving TGSM beams, and the appeal of these beams in several applications, very few experimental attempts have been made to generate, characterize, and study their propagation properties [8,12,[22][23][24][25][26]. The experimental setup used in [8] consisted of a complex optical system which was the combination of six-cylindrical lenses and a variable-coherence anisotropic GSM source.…”