By analysis of the far-field cross-correlation function (CCF) of partially coherent optical beams, we demonstrate an implicit rule that the number of ring dislocations (dark zones) of the far-field CCF is equal to the original topological charge of an optical vortex rendered partially coherent. This novel link between an optical vortex and its correlation singularity may offer an efficient method for measuring the orbital angular momentum of partially coherent optical vortices in fields such as astrophysics and astronomy, as well as atmospheric laser communication.
© 2012 Optical Society of America
Coherence and Statistical Optics
Original Manuscript: September 3, 2012
Revised Manuscript: October 22, 2012
Manuscript Accepted: October 24, 2012
Published: November 28, 2012
Yuanjie Yang, Michael Mazilu, and Kishan Dholakia, "Measuring the orbital angular momentum of partially coherent optical vortices through singularities in their cross-spectral density functions," Opt. Lett. 37, 4949-4951 (2012)