Metalenses Sorts Color Without Color Filters

Polarization-insensitive metasurface lenses (metalenses) sort primary colors on high-density pixels without the use of color filters. The metalenses simultaneously act as pixel-scale color splitters and lenses and are compatible with complementary metal–oxide-semiconductor sensor technology. An image sensor with such metalenses significantly enhances the detected light power, while affording high image quality, incident angle tolerance, and sub-micrometer spatial resolution. The demonstrated architecture opens the way to the development of high-sensitivity color image sensors that exceed current limits while maintaining consistency with state-of-the-art sensor technology.

Unlike software approaches, this hardware approach guarantees correct, software-artifact-free results. It is CMOS-compatible.

Above – Concept of an image sensor with full-color-sorting metalenses. (a) Schematic side view of a conventional color image sensor employing on-chip color filters and lenses, where only ∼30% of the incident light can reach photodetectors. (b) Schematic side view of a color image sensor employing on-chip color splitters, where all the incident light can reach photodetectors in principle. (c) Schematic of an image sensor with a full-color-sorting metalens array. The metalens implements the functionality of both a color splitter and lens and can be directly integrated on sensor pixels. (d) Illustration of the function of the metalens array. All the incident light is sorted and focused into four different pixels according to its color.

This work highlights could help enable metasurface platforms to flatten and shrink optics but also drastically enhancing the performance of consumer optoelectronics devices.

SOURCES – Optica Journal
Written by Brian Wang,