Wide-angle and high-efficiency achromatic metasurfaces for visible light

TL;DR

This paper introduces a novel achromatic metasurface capable of wide-angle, high-efficiency wavefront shaping in visible light, overcoming previous limitations of narrow incident angles and low efficiency.

Contribution

The authors develop a metasurface with metallic nano-groove gratings supporting enhanced diffraction over wide angles, enabling achromatic flat lenses with high efficiency and broad incident angle range.

Findings

Achromatic flat lens focusing multiple wavelengths at the same point.

Wide incident angle operation from 10° to 80° with high efficiency.

Suppression of specular reflection for improved performance.

Abstract

Recently, an achromatic metasurface was successfully demonstrated to deflect light of multiple wavelengths in the same direction and it was further applied to the design of planar lenses without chromatic aberrations [Science, 347, 1342(2015)]. However, such metasurface can only work for normal incidence and exhibit low conversion efficiency. Here, we present an ultrawide-angle and high-efficiency metasurface without chromatic aberration for wavefront shaping in visible range. The metasurface is constructed by multiple metallic nano-groove gratings, which support enhanced diffractions for an ultrawide incident angle range from 10o to 80o due to the excitations of localized gap plasmon modes at different resonance wavelengths. Incident light at these resonance wavelengths can be efficiently diffracted into the same direction with complete suppression of the specular reflection. This approach is applied to the design of an achromatic flat lens for focusing light of different wavelengths into the same position. Our findings provide a facile way to design various achromatic flat optical elements for imaging and display applications.