Nanophotonic Color Routing

Recent advances in low‐dimensional materials and nanofabrication technologies have stimulated many breakthroughs in the field of nanophotonics such as metamaterials and plasmonics that provide efficient ways of light manipulation at a subwavelength scale. The representative structure‐induced spectral engineering techniques have demonstrated superior design of freedom compared with natural materials such as pigment/dye. In particular, the emerging spectral routing scheme enables extraordinary light manipulation in both frequency‐domain and spatial‐domain with high‐efficiency utilization of the full spectrum, which is critically important for various applications and may open up entirely new operating paradigms. In this review, a comparative introduction on the operating mechanisms of spectral routing and spectral filtering schemes is given and recent progress on various color nanorouters based on metasurfaces, plasmonics, dielectric antennas is reviewed with a focus on the potential application in high‐resolution imaging. With a thorough analysis and discussion on the advanced properties and drawbacks of various techniques, this report is expected to provide an overview and vision for the future development and application of nanophotonic color (spectral) routing techniques. Nanoscale color routing is reviewed with a focus on the emerging concepts and the technology development trend, in particular for the applications in high‐resolution imaging. Nanophotonic methods to manipulate light in both frequency‐domain and spatial‐domain with high‐efficiency utilization of the full spectrum are presented. The remaining challenges and the potential solutions are also discussed.