Fig. 1. (a) Sketch of basic MRSRR unit on top of the silica glass substrate, L=150  nm, cell const Λ=250  nm, and gold thickness t=100  nm; L1+L2=175  nm. (b) Phase shifts and scattering amplitudes of the cross-polarized transmittance with a LCP incidence at the wavelength of 808 nm. Images of the selected nine MRSRR antennas correspond to different phase delays. (c) Phase shifts at different x positions of the metalens, and the corresponding MRSRR antennas are also placed at the bottom of the image.

Fig. 2. Full-wave simulations are performed for the propagation of a normally incident CP wave at 808 nm through the MRSRR metalens. (a) The electric field, field intensity, and phase distribution indicate that the metalens is a positive lens for LCP incident light, and (b) shows that the metalens is a negative lens for RCP incident light.

Fig. 3. Intensity distribution of the transmitted RCP light through the designed MRSRR metalenses with different focal lengths of 4.04, 8.08, and 12.12 μm, respectively, on the x–z plane, under LCP incidence at the wavelength of 808 nm.

Fig. 4. Intensity distribution of the transmitted RCP light through the designed MRSRR metalens on the x–z plane, under LCP incidence at different incident wavelengths of 740, 808, and 950 nm, respectively.

Fig. 5. Intensity distribution of the transmitted RCP light for the designed MRSRR metalenses with different NAs of 0.43, 0.53, and 0.71 on the x–z plane, under LCP incidence at a wavelength of 808 nm.