Dynamic control of luminescence chirality through achiral metasurfaces

TL;DR

This paper introduces achiral metasurfaces capable of dynamically controlling and tuning the chirality of luminescence, achieving high purity and reversibility, which advances the development of tunable circularly polarized light sources.

Contribution

It demonstrates that achiral metasurfaces can be used to actively and continuously tune luminescence chirality, overcoming limitations of chiral luminophores and chiral metasurfaces.

Findings

Achieved a maximum glum of 1.65 in experiments.

Demonstrated active tuning of glum between 1.65 and -1.58.

Validated concept with upconversion nanoparticles and dye molecules.

Abstract

Circularly polarized light (CPL) sources are essential for chiroptics, spintronics, quantum optics, and asymmetric photochemistry. However, conventional approaches fail to simultaneously realize a large luminescence dissymmetry factor (glum) and wide-range tuning of glum in a compact device. Chiral luminophores usually suffer from low glum due to their small molecular sizes. Although chiral metasurfaces can enable a large glum, they lack post-fabrication tunability. Here, we demonstrate that it is possible to achieve high-purity circularly polarized luminescence using achiral metasurfaces. These metasurfaces enable optical tuning and even reversal of luminescence chirality by uncovering and utilizing giant near-field chirality. We validate our concept with upconversion nanoparticles and downshifting dye molecules, experimentally achieving a large glum of up to 1.65, which can be actively and continuously tuned between 1.65 and -1.58. Our approach promises important applications in next-generation CPL sources and detectors, and tunable quantum devices.