Tunable Polarization-Multiplexed Achromatic Dielectric Metalens

TL;DR

This paper presents an electrically tunable, polarization-multiplexed, achromatic dielectric metalens capable of broadband varifocal imaging, integrating liquid crystals and advanced optimization to overcome chromatic aberration for versatile optical applications.

Contribution

It introduces a novel tunable metalens design that achieves broadband achromatic performance and polarization multiplexing using liquid crystals and particle swarm optimization.

Findings

Achieves broadband achromatic focusing in the visible spectrum.

Demonstrates electrically tunable varifocal and switchable color holograms.

Enables applications in broadband imaging and AR/VR displays.

Abstract

Tunable metasurfaces provide a compact and efficient strategy for optical components that require active wavefront shaping. Varifocal metalens is one of the most important applications. However, the existing tunable metalens rarely serves broadband wavelengths restricting their applications in broadband imaging and color display due to chromatic aberration. Herein, we demonstrate an electrically tunable polarization-multiplexed varifocal achromatic dielectric metalens integrated with twisted nematic liquid crystals (TNLCs) in the visible region. The phase profiles at different wavelengths under two orthogonal polarization channels are customized by the particle swarm optimization algorithm and optimally matched with the metaunits database to achieve polarization-multiplexed dispersion manipulation including achromatic performance. By combining the broadband linear polarization conversion ability of TNLC, the tunability of varifocal achromatic metalens is realized by applying different voltages. Further, the electrically tunable customized dispersion-manipulated metalens and switchable color metaholograms are demonstrated. The proposed devices will accelerate the application of metasurfaces in broadband zoom imaging, AR/VR displays, and spectral detection.