Metasurface Techniques in High-Performance Image Sensors

Metasurface techniques harness arrays of engineered nanostructures to manipulate light at scales below its wavelength, enabling unprecedented control over spectral, polarimetric and angular properties directly at the sensor interface. By replacing bulky refractive optics and absorptive colour filters with flat, nanostructured layers, image sensors achieve higher optical efficiency, enhanced sensitivity in low-light conditions and extended multispectral capabilities spanning visible to infrared bands. Recent advances in inverse-design algorithms and three-dimensional nanopatterning have facilitated multifunctional meta-optics that sort, focus and direct light into specific detector regions, offering new paths to subwavelength pixel architectures. Integration with CMOS technology has yielded compact, high-resolution cameras for applications from consumer electronics and autonomous vehicles to biomedical diagnostics and environmental monitoring. The global drive for miniaturisation, energy efficiency and richer imaging data streams underscores the transformative potential of metasurfaces in next-generation high-performance image sensors.

Research from Nature Portfolio

Advanced three-dimensional meta-optics have been realised using two-photon lithography and inverse design to create multilayer structures that sort mid-infrared light by wavelength, polarisation and angular momentum before it reaches a focal-plane array. These devices achieve highly nontrivial scattering transformations with submicrometre features and demonstrate the viability of volumetric metasurfaces for direct sensor integration.

An inverse-designed pixel-level metasurface colour router has doubled energy utilisation efficiency compared with conventional Bayer filters, achieving peak collection efficiencies of around 58 – 59 % for red and green and 49 % for blue light across the visible spectrum. A prototype atop a monochromatic sensor produced colour images with twice the intensity of standard systems, heralding next-generation compact imaging modules.

Subwavelength pixelated CMOS sensors based on anti-Hermitian metasurfaces exploit structural rather than absorptive filtering to sort red, green and blue over a 100 nm bandwidth with high colour purity and quantum efficiency. These arrays, featuring responsivities exceeding 0.25 A/W per channel, validate a route to subwavelength pixels without optical or electrical crosstalk penalties.

Metasurface Techniques in High-Performance Image Sensors publication trend

The graph below shows the total number of articles in metasurface techniques in high-performance image sensors across all publications each year (not limited to Nature Index journals).

Technical terms

Metasurface: A planar or three-dimensional array of nanostructures engineered to control light at subwavelength scales by modulating its phase, amplitude or polarisation.

Metalens: A flat, ultra-thin lens composed of metasurface elements that focuses or directs light without relying on curved glass.

Colour router: A metasurface device that spatially separates distinct wavelength bands onto designated pixel regions for efficient spectral imaging.

Anti-Hermitian metasurface: A metasurface design exploiting non-Hermitian coupling to achieve near-unity photon sorting efficiency and absorption within subwavelength pixel arrays.

Polarimetric sorting: The technique of distinguishing and directing light based on its polarisation state using bespoke metasurface architectures.

References

1. 3D-patterned inverse-designed mid-infrared metaoptics. Nature Communications (2023).
2. Pixel-level Bayer-type colour router based on metasurfaces. Nature Communications (2022).
3. Subwavelength pixelated CMOS color sensors based on anti-Hermitian metasurface. Nature Communications (2020).
4. A metasurface color router facilitating RGB-NIR sensing for an image sensor application. Nanophotonics (2024).
5. Full-color-sorting metalenses for high-sensitivity image sensors. Optica (2021).
6. Subwavelength Bayer RGB color routers with perfect optical efficiency. Nanophotonics (2022).