Figure 16.

Compact aberration-corrected spectrometer. (a) Scanning electron micrographs of a fabricated aberration-corrected off-axis metalens. (b) A regular Berry-phase lens and (c) an aberration-corrected metalens. The metalenses designed with focal length $f$ = 40 mm and focusing angle $a$ = 25 degrees at wavelength $\lambda$ = 470 nm. The focusing planes for each case are indicated by bold lines; the dashed line in the left is horizontal and meant as a reference to the curved focal plane. (Reproduced from [107] with permission.)