High‐transmission dielectric metasurface with 2π phase control at visible wavelengths

TLDR

Metasurfaces enable local manipulation of light’s amplitude, phase, and polarization, and transmissive high‑index dielectric metasurfaces offer low losses and compatibility with standard industrial processes. Numerical and experimental results show that a uniform array of silicon nanodisks achieves near‑unity transmission at visible‑wavelength resonances, while a single‑layer gradient metasurface delivers about 45 % transmission into the desired diffraction order, surpassing state‑of‑the‑art performance through simultaneous magnetic and electric dipole resonances that enable broadband forward scattering; the CMOS‑compatible, easily fabricated design is promising for flat optical devices. An illustrative image accompanies the paper.

Abstract

Abstract Recently, metasurfaces have received increasing attention due to their ability to locally manipulate the amplitude, phase and polarization of light with high spatial resolution. Transmissive metasurfaces based on high‐index dielectric materials are particularly interesting due to the low intrinsic losses and compatibility with standard industrial processes. Here, it is demonstrated numerically and experimentally that a uniform array of silicon nanodisks can exhibit close‐to‐unity transmission at resonance in the visible spectrum. A single‐layer gradient metasurface utilizing this concept is shown to achieve around 45% transmission into the desired order. These values represent an improvement over existing state‐of‐the‐art, and are the result of simultaneous excitation and mutual interference of magnetic and electric‐dipole resonances in the nanodisks, which enables directional forward scattering with a broad bandwidth. Due to CMOS compatibility and the relative ease of fabrication, this approach is promising for creation of novel flat optical devices. image