Fig. 3: Spectral 3D tomographic imaging.
a Schematics of the imaging setup. Lighting source is a halogen lamp. The four pictures in the inset are images through an achromatic objective O2 (×40, NA = 0.75) and are used as objects with different depths for the metalens to verify the tomographic imaging. The scale bar is 10 μm. The marked distances are measured distances from the metalens. The experiment captured images through an achromatic objective O1 (×100, NA = 0.70) and a CCD for the cases of (b) the aplanatic metalens and (c) the normal metalens for the same numerical aperture (NA = 0.78)
