Broadband achromatic optical metasurface devices

TLDR

Metasurfaces enable efficient manipulation of light but suffer from large chromatic aberration due to the high phase dispersion of their building blocks. We propose a design principle to realize achromatic metasurface devices that eliminate chromatic aberration over 1200–1680 nm for circularly polarized light in a reflection scheme. The approach tailors the phase response of the metasurface elements in a reflection configuration to achieve broadband achromatic behavior from 1200 to 1680 nm. We demonstrate broadband achromatic metalenses with ~12 % efficiency that focus arbitrary wavelengths to the same focal plane, and a gradient metasurface that deflects wide‑band light by a constant angle, enabling previously impossible flat achromatic devices for full‑color detection and imaging.

Abstract

Abstract Among various flat optical devices, metasurfaces have presented their great ability in efficient manipulation of light fields and have been proposed for variety of devices with specific functionalities. However, due to the high phase dispersion of their building blocks, metasurfaces significantly suffer from large chromatic aberration. Here we propose a design principle to realize achromatic metasurface devices which successfully eliminate the chromatic aberration over a continuous wavelength region from 1200 to 1680 nm for circularly-polarized incidences in a reflection scheme. For this proof-of-concept, we demonstrate broadband achromatic metalenses (with the efficiency on the order of ∼12%) which are capable of focusing light with arbitrary wavelength at the same focal plane. A broadband achromatic gradient metasurface is also implemented, which is able to deflect wide-band light by the same angle. Through this approach, various flat achromatic devices that were previously impossible can be realized, which will allow innovation in full-color detection and imaging.