Contrast-Enhanced Nonlinear Imaging with Moiré Flatband Superlattices
Abstract
Nonlinear metasurfaces offer a compact platform for infrared-to-visible conversion and imaging, yet resonant enhancement is often accompanied by restricted angular acceptance, limiting the range of transverse spatial frequencies that can interact efficiently with the nonlinear modes. Here, we address this challenge using a one-dimensional photonic moiré superlattice supporting multiple quasi-flat bands in the near-infrared. These moiré modes combine strong near-field enhancement with broad momentum-space accessibility, enabling efficient third-harmonic generation (THG) while maintaining stable excitation over a large angular range. Experimentally, we observe strong THG emission near 467 nm under broadband excitation from $ 1180$ to $ 2000~\mathrm {nm} $. We further employ the nonlinear moiré superlattice for infrared imaging by converting an infrared target into visible through the THG process. By encoding image information into displacement-dependent THG signals and decoding their spatial variations, we experimentally resolve weak features and internal textures with improved contrast compared with THG imaging using nonlinear films or conventional nonlinear metasurfaces. These results establish photonic moiré superlattices as a versatile platform combining efficient frequency conversion, broad angular acceptance, and mode-sensitive spatial encoding for high-contrast, label-free nonlinear imaging with enhanced feature discrimination.
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BibTeX
@misc{zamani2026contrastenhanced,
title = {{Contrast-Enhanced Nonlinear Imaging with Moiré Flatband Superlattices}},
author = {Amin Zamani and Lihang Feng and Jianji Liu and Ze Zheng and Gabriel Sanderson and Mohsen Rahmani and Peilong Hong and Lei Xu},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.03951},
eprint = {2611.03951},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.03951},
}
RIS
TY - UNPB
TI - Contrast-Enhanced Nonlinear Imaging with Moiré Flatband Superlattices
AU - Amin Zamani
AU - Lihang Feng
AU - Jianji Liu
AU - Ze Zheng
AU - Gabriel Sanderson
AU - Mohsen Rahmani
AU - Peilong Hong
AU - Lei Xu
PY - 2026
DA - 2026/11/02
PB - arXiv
DO - 10.48550/arxiv.2611.03951
UR - https://arxiv.org/abs/2611.03951
AB - Nonlinear metasurfaces offer a compact platform for infrared-to-visible conversion and imaging, yet resonant enhancement is often accompanied by restricted angular acceptance, limiting the range of transverse spatial frequencies that can interact efficiently with the nonlinear modes. Here, we address this challenge using a one-dimensional photonic moiré superlattice supporting multiple quasi-flat bands in the near-infrared. These moiré modes combine strong near-field enhancement with broad momentum-space accessibility, enabling efficient third-harmonic generation (THG) while maintaining stable excitation over a large angular range. Experimentally, we observe strong THG emission near 467 nm under broadband excitation from $ 1180$ to $ 2000~\mathrm {nm} $. We further employ the nonlinear moiré superlattice for infrared imaging by converting an infrared target into visible through the THG process. By encoding image information into displacement-dependent THG signals and decoding their spatial variations, we experimentally resolve weak features and internal textures with improved contrast compared with THG imaging using nonlinear films or conventional nonlinear metasurfaces. These results establish photonic moiré superlattices as a versatile platform combining efficient frequency conversion, broad angular acceptance, and mode-sensitive spatial encoding for high-contrast, label-free nonlinear imaging with enhanced feature discrimination.
ER -