Broadband metasurfaces for morphograms constructed from grafted vector trajectory beams.

Traditional perfect vector vortex beams (PVVBs) and their arrangements are constrained by azimuthal phase variations. This restricts them to hollow circular or elliptical geometries as well as planar or concentric arrays. To overcome this, we propose a metasurface-based scheme for generating morphograms from grafted vector trajectory beams (VTBs). By mapping the phase along the trajectory via equal-arc-length sampling, we customize arbitrary shapes while ensuring linear polarization evolution along the trajectory path. Integrating phase-grafting technology further enables piecewise modulation of phase and polarization along the trajectory path. Furthermore, non-overlapping arrangements of independent VTBs significantly enhance spatial layout flexibility. This broadband platform holds great potential for high-capacity optical encryption and multidimensional light-field manipulation.