An electrically tunable metaatom for visible light

TL;DR

This paper introduces an electrically tunable metaatom operating in the visible spectrum, enabling dynamic wavefront control and rewritable holograms through reversible doping of a conducting polymer.

Contribution

It presents a novel electrically tunable metaatom based on excitonic absorption in a conducting polymer, functioning in the visible range, unlike previous static or infrared-only designs.

Findings

Demonstrated electrically tunable phase-gradient metasurfaces for visible light.

Achieved erasable and rewritable holograms using the metaatom.

Reversible doping allows dynamic control of optical properties.

Abstract

Phase-gradient metasurfaces provide powerful wavefront control through two-dimensional arrangement of nanostructures acting as metaatoms. While dynamic tuning forms a major driver for future breakthroughs and applications in this area, current metaatoms are generally static or limited to operation in the infrared. Here, we present a metaatom that is both electrically tunable and operates in the visible. Its function originates from an excitonic absorption band of a dedoped conducting polymer, which together with low background permittivity induces optical metallicity in a selected part of the visible. This allows anisotropic nanostructures to support excitonic resonances along one direction and not the other, promoting polarization-dependent optical response which can be toggled off and on through reversible doping induced by small bias potentials. Our study details the mechanism of these metaatoms and demonstrate their use in electrically tunable phasegradient metasurfaces for visible light, including erasable and rewritable holograms.