Generating topological non-diffracting beams using high quality factor nonlocal metasurfaces

Fuente: arXiv
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Main Authors: Kim, Dongha, Pelzman, Charles, Guo, Cheng, Long, Olivia Y., Fan, Shanhui, Cho, Sang Yeon
Format: Preprint
Published: 2025
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_version_ 1866912617917841408
author Kim, Dongha
Pelzman, Charles
Guo, Cheng
Long, Olivia Y.
Fan, Shanhui
Cho, Sang Yeon
author_facet Kim, Dongha
Pelzman, Charles
Guo, Cheng
Long, Olivia Y.
Fan, Shanhui
Cho, Sang Yeon
contents Non-diffracting optical beams are essential tools in photonics, enabling robust light transport, super-resolution imaging, and spatiotemporal control. While nonlocal metasurfaces have been proposed for structured-light generation due to their broad angular dispersion and topological characteristics, experimental generation of a non-diffracting beam with nonlocal metasurfaces has not been demonstrated. Here we experimentally realize vortex Bessel beams using a nonlocal metasurface and establish a direct link between non-diffracting-beam generation and photonic band curvature. Depending on the sign of the curvature, the beams exhibit spatially asymmetric non-diffraction, emerging either in front of or behind the metasurface. This asymmetry arises from a radial phase gradient in momentum space, which induces effective space compression or expansion. Furthermore, we demonstrate wavelength-dependent tunability of the beam diameter and propagation distance, and show an order-of-magnitude enhancement in propagation distance compared to conventional Laguerre--Gaussian modes. These results position nonlocal metasurfaces as a compact, tunable platform for spatiotemporally controlled non-diffracting light.
format Preprint
id arxiv_https___arxiv_org_abs_2509_26142
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Generating topological non-diffracting beams using high quality factor nonlocal metasurfaces
Kim, Dongha
Pelzman, Charles
Guo, Cheng
Long, Olivia Y.
Fan, Shanhui
Cho, Sang Yeon
Optics
Non-diffracting optical beams are essential tools in photonics, enabling robust light transport, super-resolution imaging, and spatiotemporal control. While nonlocal metasurfaces have been proposed for structured-light generation due to their broad angular dispersion and topological characteristics, experimental generation of a non-diffracting beam with nonlocal metasurfaces has not been demonstrated. Here we experimentally realize vortex Bessel beams using a nonlocal metasurface and establish a direct link between non-diffracting-beam generation and photonic band curvature. Depending on the sign of the curvature, the beams exhibit spatially asymmetric non-diffraction, emerging either in front of or behind the metasurface. This asymmetry arises from a radial phase gradient in momentum space, which induces effective space compression or expansion. Furthermore, we demonstrate wavelength-dependent tunability of the beam diameter and propagation distance, and show an order-of-magnitude enhancement in propagation distance compared to conventional Laguerre--Gaussian modes. These results position nonlocal metasurfaces as a compact, tunable platform for spatiotemporally controlled non-diffracting light.
title Generating topological non-diffracting beams using high quality factor nonlocal metasurfaces
topic Optics
url https://arxiv.org/abs/2509.26142