Fig. 3

The measured intensity profiles of the VBs along the propagating direction for the metasurface zone plates with topological charges of (a-d) l = 2 and (i-l) l = 3 at different wavelengths of (a, i) 633 nm, (b, j) 600 nm, (c, k) 570 nm, and (d, l) 532 nm. e-h and m-p are measured intensity profiles at the focal planes corresponding to (a-d) and (i-l). Scale bar: 10 μm. All the images are shown in false-color