Micrometer-resolution 3D imaging Lidar based on metalens with strong chromatic dispersion

In recent years, metalens showed their applied potential as depth information sensors. To combine the advantages of active-imaging Lidar and the depth information acquisition ability of metalens, a 3D imaging setup based on metalens array with strong chromatic dispersion was proposed in this paper. When the scene was illuminated by the laser with different wavelengths, the point spread function (PSF) of points in the scene was varied at a certain imaging plane behind the metalens. Only when the point located on the object plane was illuminated by a certain wavelength the optimized PSF could be observed on the imaging plane. Therefore, by measuring the PSFs of a pairs of defocus images induced by the chromatic dispersion of the metalens the absolute distance from metalens to a point on the scene could be obtained. Combined with the clear 2D image, 3D imaging can be realized. When the chromatic dispersion of the metalens is stronger, PSF is more sensitive to the distance change, higher distance measurement resolution can be obtained. The simulation results of metalens with different dispersion shown in the paper proved our assumption.