Fig. 1. Schematic diagram of organization in this review.

Fig. 2. (a) Phase profile for a broadband achromatic metalens. (b) Schematic diagrams and phase spectra of three types of IRUs with phase compensations of Δφ1(λ), Δφ2(λ), and Δφ3(λ), respectively.

Fig. 3. Achromatic integrated-resonant metadevices: IRUs and intensity distributions at different wavelengths. (a) Coupled rectangular silicon resonators, three discrete wavelengths of 1300, 1550, and 1800 nm.⁴³ (b) TiO2 nanopillars tiled on a SiO2 spacer layer above an Al-coated fused silica substrate, narrowband from 490 to 550 nm.⁴⁴ (c) Au nanorods, broadband from 1200 to 1680 nm.³³ (d) GaN nanopillars and nanoholes, broadband from 400 to 660 nm.⁴⁵ (e) TiO2 nanofins, broadband from 470 to 670 nm.⁴⁶ (f) Silicon nanopillars, broadband from 1200 to 1650 nm.⁴⁷

Fig. 4. Efficiency-enhanced integrated-resonant metadevices: schematic diagrams, scanning electron microscope (SEM) images, and spectral responses. (a) Al multinanorods to enhance broadband polarization conversion efficiency.³⁸ (b) Four VSRRs for isotropic perfect absorption.⁵⁴ (c) 3D Au/Si3N4 Archimedean spirals to enhance the optical chirality.⁵⁵ (d) Coupled Au pillars and gratings used for a high Q factor under highly focused incidence.⁵⁶ (e) Silicon nanodisks with Kerker condition to achieve high transmission accompanied by full 2π phase coverage.⁵⁷ (f) VSRRs covered with a perforated Au film to excite the anapole mode.⁵⁸ (g) Silicon rectangular bar resonators combined with ring resonators to generate the Fano resonance.⁵⁹ (h) AlGaAs nanodisk with mode coupling to form quasi-BIC.⁶⁰

Fig. 5. Property-selective integrated-resonant metadevices. (a) Two sets of silicon nanoholes with q-BIC to realize wavefront shaping at selected wavelengths: schematic diagram, SEM image, and xy and xz plane intensity distributions at different wavelengths.⁶⁹ (b) GaN nanopillars for OAM selectivity in metasurface holography: schematic diagram and experimental metaholograms with four OAM topological charges.⁷¹ (c) Diatomic Au VSRRs allow polarization-selective perfect absorption: schematic diagram, reflection spectra with different polarization states, and SEM images.⁷³ (d) U-shaped amorphous silicon nanopillars for angle-selective metahologram: schematic diagram and measured reflected images at normal and 30 deg illumination angles.⁷⁵ (e) Notched silicon bars to achieve metalens with intensity selectivity: schematic diagram and field intensity profiles with different input intensities.⁷⁶

Fig. 6. Tunable integrated-resonant metadevices. (a) TiO2 nanoposts with polarization-dependent response for varifocal metalens: schematic diagram and intensity distributions with horizontally and vertically polarized incidence.⁷⁹ (b) Coupled anisotropic silicon nanofins with thermo-optic effects to obtain thermally reconfigurable metalens: schematic diagram and intensity profiles for different temperatures.⁸¹ (c) Eight integrated CMOS switches allow digitally programmable wavefront shaping based on electric stimuli: schematic diagram, far-field intensity distributions, and fabricated metasurface chip.⁸⁴ (d) Coupled Au nanobars for environment-based dynamic metahologram: schematic diagram and hologram images with different environments.⁸⁵ (e) Interleaved Al and phase change material GST stacked nanorods utilized for all-optical cryptography: schematic diagram and hologram images for three states of GST.⁸⁹ (f) Au nanorods integrated on stretched PDMS to acquire the zoom lens: schematic diagram and beam profiles with distinct stretch ratios.⁹⁰

Fig. 7. Integrated-resonant metadevices for achromatic imaging. (a) Reflective achromatic metalens made of Au IRUs: (left) SEM image, (middle) optical image of the metalens, and (right) intensity profiles at different incident wavelengths.³³ (b) Transmissive achromatic metalens made of TiO2 IRUs in the visible: (left) image of USAF target and (right) image of Siemens star pattern.⁴⁶ (c) Transmissive achromatic metalens made of GaN IRUs in the visible: (left) SEM image, (middle) image of USAF target, and (right) full-color image of Alcedinidae.⁴⁵ (d) Achromatic polarization-insensitive metalens made of TiO2 IRUs in the visible: (left) SEM image and (right) image of USAF target corresponding to number 6.⁵² (e) Achromatic polarization-insensitive metalens made of TiO2 IRUs in the NIR spectrum: (left) SEM image, (right) results of upconversion fluorescent imaging (top row: NCs and polystyrene spheres and bottom row: HeLa cells).⁵³ (f) Achromatic metalens made of TiO2 IRUs using a neural network: (left) SEM image and (right) three letters images with different linewidths.⁹⁶

Fig. 8. Integrated-resonant metadevices for light-field sensing. (a) Imaging and reconstruction process of a depth sensor composed of TiO2 IRUs.⁹⁷ (b) (Left) Schematic diagram of integral imaging using a SiN IRUs-based achromatic metalenses array and (right) reconstructed images at different locations with various incident wavelengths.⁹⁸ (c) (Left) Schematic of light-field sensing using an achromatic metalenses array consisting of GaN IRUs and (right) reconstruction images, and depth maps with different depths.⁹⁹ (d) (Left) Schematic of edge detection relying on a GaN IRUs-based achromatic metalenses array and (right) experiment results: light-field raw data, partial raw data, 1D edge image result, 3D edge images with different depths.¹⁰⁰ (e) (Left) Schematic of 3D image system realized by TiO2 IRUs and neural network and (right) reconstruction results of full-color images and depth maps.¹⁰¹ (f) Schematic of a depth-sensing system composed of GaN IRUs in all-light-level.¹⁰²

Fig. 9. Integrated-resonant metadevices for polarization detection. (a) Schematic of Au IRUs-based spectropolarimetry.¹⁰⁷ (b) Schematic of Al IRU-based versatile polarization detector under linearly polarized incident light.¹⁰⁸ (c) (Left) Schematic of Al IRU-based visible polarimetry under incident light with unknown polarization state and (right) measurement results after the y-polarized light passes through a single layer of BOPP film.¹⁰⁹ (d) Meta-Hartmann–Shack array based on silicon IRUs: (top) intensity distributions, (middle) images with meta-Hartmann–Shack array, and (bottom) polarization profiles of focal spots for radially polarized incident beam and azimuthally polarized beam.¹¹⁰ (e) Schematic diagram and experimental results of silicon IRU-based polarization imaging system.¹¹¹ (f) Alpha-silicon IRU-based metasurfaces for polarization detection and manipulation: (top) versatile polarization generator, schematic diagram, and intensity profiles with different polarization states and (bottom) vectorial holographic display.¹¹²

Fig. 10. Integrated-resonant metadevices for OAM generation. (a) (Top) Schematic and SEM image of spin-controlled Au IRUs-based OAM generator with multimodes and (bottom) three-by-two spin-dependent OAM wavefronts with the desired topological charges.¹²⁷ (b) (Upper left) Schematic of tunable OAM generator based on GST IRUs, (upper right) interference patterns, and (bottom) diffraction profiles at different crystallization levels.¹²⁸ (c) (Top) Modulation of IRU by hydrogenation and dehydrogenation, (middle) OAM switching, and (bottom) schematic of hologram switching.¹²⁹ (d) Intensity and phase profiles with different polarization states of silicon IRU-based metadevice.¹³⁰ (e) OAM generator made of multilayer IRUs: (left) structure diagram and (right) schematic principle of the OAM generator with integer and fractional modes engineered by polarization modulation.¹³¹

Fig. 11. Integrated-resonant metadevices for metaholography. (a) Metahologram images can be switched by the states of linearly polarized light based on Au IRUs: (left) schematic of the metahologram and (right) reconstructed images.¹⁵⁵ (b) Hologram patterns of an Au IRU-based metadevice dependent on incident polarization states and wavelengths.¹⁵⁶ (c) Vectorial metahologram based on Ag IRUs: (upper left) predesigned pattern, (bottom left) SEM image, and (right) measured results of holographic images.¹⁵⁷ (d) Schematic of the polarization-sensitive multicolor metahologram composed of Al IRUs.¹⁵⁸ (e) (Left) Schematic of the 3D full-color metahologram based on silicon IRUs and (right) 3D full-color reconstructed results under RCP incident light.¹⁵⁹ (f) Reconstructed results of full-color complex-amplitude vectorial hologram based on Al IRUs, illuminating by (left) laser beam with different colors and (right) white light.¹⁶⁰

Fig. 12. Integrated-resonant metadevices for nanoprinting. (a) Polarization-sensitive nanoprinting using TiO2 IRUs: (left) schematic of setup and (right) measured meta-nanoprinting patterns under LCP/RCP illumination.¹⁶⁵ (b) Angle-multiplexing nanoprinting with hologram using Ag IRUs: (left) sketch of the metadevice and (right) experiment results of nanoprinting and holographic patterns.¹⁶² (c) Integrating color printing with holography based on silicon IRUs: (left) schematic of principle and (right) measured patterns of nanoprinting and hologram.¹⁶⁶ (d) Full-color nanoprint-hologram synchronous realization using c-silicon IRUs: (left) schematic of principle and (right) measured hologram patterns under various incident lights.¹⁶⁷ (e) (Top) Arrangement and principle of c-silicon IRUs and (bottom) schematic of displaying images in three channels.¹⁶⁸ (f) Illustration of vectorial holographic color prints with the assistance of IRU and liquid crystal.¹⁶⁹

Fig. 13. Integrated-resonant metadevices for color routing. (a) Dual-band color router with dolmen IRUs: (left) schematic of the device and (right) measured Fourier image.¹⁷⁰ (b) Tri-band color router with doublet IRUs for the wavelengths of 1180, 1400, and 1680 nm: (left) schematic of the tri-band color router and (right) measured intensity distributions and focal spot profiles.¹⁷¹ (c) Tri-band color router with nanobeams IRUs in the visible: (left) schematic of setup and (right) image generated by the color router.¹⁷² (d) Sensitivity and noise tolerance performance of tri-band color router with nanoposts IRUs: (left) comparison of the total amount of light in each configuration and (right) color images reconstructed by each configuration with different sensor noise.¹⁷³ (e) Full-color router displayed a Bayer pattern using nanopillars IRUs: (left) principle of full-color routing and (right) measured results at the focal plane under different wavelengths.¹⁷⁴ (f) Nanoposts IRUs color-sorting device: (left) focal intensity profile and (right) comparison results of color objects imaged by two sensors.¹⁷⁵

Fig. 14. Integrated-resonant metadevices for nonlinear effect. (a) THG with high efficiency based on metal–dielectric IRUs: (left) schematic of the configuration, (middle) SEM image and normalized electric field distribution, and (right) THG spectra.¹⁸² (b) THG boosted by all-dielectric IRUs: (left) TH spectra under different incident conditions of polarization states and (right) TH spectra of an unpatterned silicon film.¹⁸³ (c) Reshaping TH spectra using all-dielectric IRUs: (left) schematic diagram and (right) tuning the TH spectral response under different distances between the nanodisks.¹⁸⁴ (d) Improving the efficiency of SH power collection using AlGaAs IRUs: (left) SEM images of a disk and the IRU and their corresponding SH emission patterns and (right) fraction of SH emitted at different NAs compared to the total collected SH.¹⁸⁵ (e) Nonlinear imaging by Au IRUs: (left) SEM image of the metadevice for nonlinear hologram and (right) measured hologram image.¹⁸⁶ (f) Complex quantum states generated by GaAs IRUs: (left) schematic of generating complex quantum states and (right) SPDC spectrum to illustrate the entangled process.¹⁸⁷

Table 1. Performances of broadband achromatic metalenses.