Longitudinal manipulation of local nonseparability in vector beams.

The inherent nonseparability of vector beams presents a unique opportunity to explore novel optical functionalities, expanding new degrees of freedom for optical information processing. In this Letter, we introduce a novel, to the best of our knowledge, method for tailoring the local nonseparability along the propagation axis of vector beams. Employing higher-order Bessel vector beams, the longitudinal control over the local nonseparability is achieved through targeted amplitude modulation of constituent orthogonal polarization components within the main ring region. Experimental demonstrations of diverse longitudinal nonseparability profiles corroborate the efficacy and versatility of our approach, opening avenues for further exploration of the nonseparability manipulation in vector beams.