Multiwavelength achromatic meta-lens based on multi-focal phase profile

We demonstrate a multiwavelength achromatic meta-lens for red, green, and blue light based on multi-focal phase profile. The anisotropic rectangular nano-structure with silicon nitride is utilized for the meta-lens based on Pancharatnam-Berry phase technique. The proposed meta-lens has the focal length of 200 μ m at the maximum intensity and the numerical aperture of 0.67.