Evaluation of twisted Gaussian Schell model beams produced with phase randomized coherent fields

Abstract

The twisted Gaussian Schell Model describes a family of partially coherent beams that present several interesting characteristics, and as such have attracted attention in classical and quantum optics. Recent techniques have been demonstrated to synthesize these beams from a coherent source using a discrete set of “pseudo-modes”, where the phase of each mode is randomized so that they are mutually incoherent. Here we investigate this technique and evaluate the resulting beam parameters, such as divergence, coherence length and twist phase. We show that for a finite set of modes there is also some residual coherence, which can have an observable effect. A theoretical model is developed for the output field that includes residual coherence and agrees very well with experimental data. In addition, we demonstrate a simple method to measure the twist phase using double slit interference.

Partial nonseparability of spin-orbit modes

“…The normalized squared amplitude of each term of equation equation (14) gives us the probabilities of all possible measurements. In a quantum mechanics scenario, it is related to photon counting and in a classical approach, the intensities play the role of probabilities.…”

“…Fully-structured light opens several perspectives as optical traps sensitive to the polarization that presents potential for applications to magnetic particles and laser materials [13]. Different spatial modes, such as Gaussian Schell modes, have received special attention due to potential applications [14]. By exploring structured light we can access different symmetries as SU(2) symmetry group, present in several physical systems, including quantum analogies with an intense laser beam, where connections between ray and wave descriptions play the role of classical and quantum domain and many applications can be envisaged [15].…”