Coherence and coherence vortex embedded in partially coherent Gaussian beam background during propagation

Abstract

This work presents theoretical analysis on coherence vortex of partially coherent vortex beam (PCVB) during propagation. Complex degree of coherence is analyzed to explore the coherence singularity embedded in PCVB in detail. It is shown that observation of coherence singularity is related to position of reference point, and coherence singularities appear in pairs while the reference point is located far from the center. Detailed investigation reveals that it is easy to distinguish coherence singularity for the case of near field and for the case of original PCVB with high coherence.