Stokes scintillations for vector vortex beams with controllable spatial correlation

The present work reports the theoretical and experimental observation of Stokes scintillations (SS) for focused vector vortex beams (VVBs) with controllable spatial correlation. Initially, a Gaussian-Schell model (GSM) source is utilized to generate the partially coherent VVBs (PC-VVBs). The focusing of PC-VVBs results in the optimization of extremum values of SS parameters across the beam cross section. Additionally, the SS parameters of the focused PC-VVB show spatially structured behavior. It is found that the spatial correlation, the inhomogeneous polarization distribution, and the Poincar\'e-Hopf index (PHI) of VVBs are important factors for structuring the SS parameters. The SS parameters are observed to exhibit a complementary relationship. Furthermore, the degeneracy associated with the SS parameters is discussed to complete the study. The flower-patterned distribution of specific SS parameters is useful in determining the topological index of the PC-VVBs. Interestingly, the bound condition and complementary nature of SS parameters are useful for scintillation squeezing across the beam cross section in PC-VVBs, where one SS parameter is suppressed at the expense of another. Thus, the source can be finely tuned using the bound condition with correlation and topological features to harness this effect optimally.