Full-color nanorouter for high-resolution imaging.

Pixel scaling effects have been a major issue in the development of high-resolution color image sensors due to the reduced photoelectric signal and color crosstalk. Various structural color techniques have been proposed, and the large freedom in color manipulation by the structure design has been demonstrated. However, the optical efficiency and color distortion limit the practical applications due to their intrinsic filtering mechanism. Instead, the on-chip full-color routing is quite desirable for improving the signal-to-noise ratio. In this study, a single-layer quick response code-like nanorouter is proposed for the full-color light routing in a pixel level of image sensors. It shows much higher routing efficiency than various planar lens schemes for signal wavelength focusing. Moreover, over 60% signal enhancement with robust polarization insensitivity is obtained in all three primary color bands with the same nanorouter by a multi-objective optimization method. Negligible color distortion is observed from the reconstructed color image. Such a simple nanorouter scheme is promising for the development of image sensors, photovoltaics and displays.