Fig. 1. Architecture and characterization of PMID. (a) Schematic of the chip-scale PMID. (b) Photographic image of the PMID with bottom-left inset for the side-view of the zoomed-in image, and upper-right inset for the SEM image of the SiNx metalens. (c) Imaging results of USAF resolution chart taken through the metalenses without CPF in 1×, 2×, 3× image magnifications, whose NA=0.33, 0.35, and 0.45, with SNR equal to 23.46, 16.22, and 13.01 dB, respectively. (d) The counterpart images taken through the PMID (with the CPF) with respect to (c) resulting in SNR=30.37, 24.60, 27.60 dB, respectively. Scale bar: 50μm. (e) The intensity distributions of horizontal lines (HLs) of in red/blue solid boxes in (c) and (d), corresponding to the resolution elements of g8e2 (1.74μm), g8e6 (1.1μm), and HL of g9e2 (870 nm), respectively, for three cases. (f) The experimental and theoretically limited MTF of three imaging results. (g) Measured resolution of singlet-metalens PMIDs with different NA. The black line is the diffraction-limited, while the red stars are the experimental results and the red points in the black line are the theoretical resolutions of the designed metalenses.

Fig. 2. Independent dual-phase design for co- and cross-circularly polarized light. (a) Schematics of the design principle: a single metasurface obtains two independent phase modulations for each incident circular polarization light after fixed CPF (for RCP). Simulated phase responses of the transmitted (b) RCP and (c) LCP light with the nanofins structural parameters under RCP incidence. (d) Amplitude distribution of the selected nanofin structures, where red circles and blue squares correspond to co-polarized (b) and cross-polarized (c) phase modulations, respectively. The simulated intensity distributions of a transverse bifocal metalens on the focal plane with CPF for (e) x-polarized, (f) LCP, and (g) RCP light incidence.

Fig. 3. Imaging of the chip-scale PMID. (a) Phase distribution of part of the chip-scale metalens in the x–y plane. The lattice A (blue) and lattice B (red) correspond to the phase distributions for LCP and RCP light incidence, respectively. (b) Top-view photographic images of the chip-scale PMID (left), the 16×16 metalens array (middle), and optical microscope image of a 2×2 metalens array (right). (c) Raw images of the USAF resolution test chart with LCP and RCP light incidence. (d) Stitched image from subimages of (c). The region in the red circle corresponds to the FOV of the microscope. (e) Zoomed-in stitched image (right) and image obtained with the Olympus microscope (10×, NA=0.25) (left) to show the resolution. Scale bar: 40μm.

Fig. 4. Wide-field and DOF imaging. (a) Schematic of the cell solution container. (b) Top-view photographic image of the cell solution container. Scale bar: 5 mm. (c) Stitched image of HUVECs in solution. (d) Zoomed-in images of the red box in (c) at 450, 470, 490, and 510 nm, respectively. Scale bar: 100μm. Wide view living observations of flowing HUVECs in a solution with PMID (Video 1, MP4, 7.17 MB [URL: https://doi.org/10.1117/1.AP.4.4.046006.1]).

Fig. 5. Compact prototype of the chip-scale PMID. (a) Photographic image of the traditional Olympus microscope together with the PMS prototype. (b) Photographic image of the PMS prototype (3cm×3.5cm×4cm). (c) Stitched image of pine stem c.s. at 470 nm. Zoomed-in image (c1) and image (c2) taken by the Olympus microscope (10×). The operation of PMS (Video 2, MP4, 11.7 MB [URL: https://doi.org/10.1117/1.AP.4.4.046006.2]).