Symmetry-governed nonlinear metasurface simultaneously enhances circular dichroism, helicity purity, and Q-factor
Abstract
Circularly polarized light underpins a broad range of chiroptical and spin-selective photonic technologies, yet extending resonant chirality to nonlinear harmonic emission remains challenging. Here, we experimentally demonstrate a symmetry-governed mechanism that maps the maximal linear chirality of high-Q degenerate resonances onto the polarization of the generated harmonic. Preserved rotational symmetry protects modal degeneracy and polarization-selection rules, while broken mirror symmetries enable a strong chiroptical response. The metasurface thereby filters the pump polarization and purifies the handedness of the nonlinear output, simultaneously achieving third-harmonic circular dichroism of -0.98, a degree of circular polarization of 0.83, and an effective nonlinear Q-factor of 140. Importantly, the nonlinear emission preserves its handedness even under spatially depolarized excitation, demonstrating robustness to variations in the incident polarization state. These results establish complementary symmetry preservation and breaking as a deterministic route for transferring resonant chirality from linear to nonlinear optical responses, providing a general design principle for nonlinear chiral photonics.
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BibTeX
@misc{gromyko2026symmetrygoverned,
title = {{Symmetry-governed nonlinear metasurface simultaneously enhances circular dichroism, helicity purity, and Q-factor}},
author = {Dmitrii Gromyko and Wenhe Jia and Chengfeng Pan and Xuan Mao and Wenduo Chen and Zhen Xu and Shutao Zhang and Hongtao Wang and Bochang Wu and Wang Hao and Sergei Tikhodeev and Qijie Wang and Joel K. W. Yang and Cheng-Wei Qiu and Lin Wu},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.39565},
eprint = {2610.39565},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.39565},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Symmetry-governed nonlinear metasurface simultaneously enhances circular dichroism, helicity purity, and Q-factor
AU - Dmitrii Gromyko
AU - Wenhe Jia
AU - Chengfeng Pan
AU - Xuan Mao
AU - Wenduo Chen
AU - Zhen Xu
AU - Shutao Zhang
AU - Hongtao Wang
AU - Bochang Wu
AU - Wang Hao
AU - Sergei Tikhodeev
AU - Qijie Wang
AU - Joel K. W. Yang
AU - Cheng-Wei Qiu
AU - Lin Wu
PY - 2026
DA - 2026/10/29
PB - arXiv
DO - 10.48550/arxiv.2610.39565
UR - https://arxiv.org/abs/2610.39565
AB - Circularly polarized light underpins a broad range of chiroptical and spin-selective photonic technologies, yet extending resonant chirality to nonlinear harmonic emission remains challenging. Here, we experimentally demonstrate a symmetry-governed mechanism that maps the maximal linear chirality of high-Q degenerate resonances onto the polarization of the generated harmonic. Preserved rotational symmetry protects modal degeneracy and polarization-selection rules, while broken mirror symmetries enable a strong chiroptical response. The metasurface thereby filters the pump polarization and purifies the handedness of the nonlinear output, simultaneously achieving third-harmonic circular dichroism of -0.98, a degree of circular polarization of 0.83, and an effective nonlinear Q-factor of 140. Importantly, the nonlinear emission preserves its handedness even under spatially depolarized excitation, demonstrating robustness to variations in the incident polarization state. These results establish complementary symmetry preservation and breaking as a deterministic route for transferring resonant chirality from linear to nonlinear optical responses, providing a general design principle for nonlinear chiral photonics.
ER -