Fig. 5: Experimentally measured focal fields of the investigated lenses.

Experimental results for a conventional glass lens (a–e), the metalens without additional grating phase (f–j), and for the metalens with a superposed grating phase (k–o). Subfigures a, f and k show the images of the focal plane as they were recorded; subfigures b, g and i depict background-corrected versions of these, scaled to the actual dimensions of the focal field, and added indications of the profiles that were taken, which are shown in subfigures c, d, h, i, m and n. Finally, subfigures e, j and o show the profiles along the optical axis, including a regression line (dotted red line) to indicate the depth of field.