Spatially structured light fields and their propagation manipulation

The spatially structured light fields (SSLFs) with laterally inhomogeneous amplitude, phase, and polarization distributions have shown many extraordinary properties beyond the Gaussian light fields, providing new insight into fundamental advances and becoming vital tools to overcome the problems in applications such as optical manipulation, superresolution imaging, classical and quantum communications and so on. With the development, the spatial dimension involved in light field manipulation has been gradually expanded from two-dimensional plane to three-dimensional space. Therefore, revealing the evolution properties of laterally structured light fields is prerequisite for realizing high-dimensional manipulation of light field and utilizing high-dimensional information. Here we review the propagation manipulation of SSLFs. We start with the introduction of SSLFs with laterally structured phase and polarization, i.e., scalar and vector SSLFs, from eigenmode of wave equation towards generic SSLFs with arbitrary spatial phase and polarization structures. Then, we focus on the propagation characteristics and the evolution of the lateral structures of SSLFs, and reveal the propagation manipulation of scalar and vector light fields. We discuss the remarkable features of light fields and the singularity transformation in special and generic vortex and vector beams, and describe elaborate three-dimensional structures associated with propagation manipulation, e.g., vortex topological structure, spin Hall effect of light, optical activity and so on. The discussed phenomena inspire us to explore higher dimensional manipulation of light fields and their applications.