Work

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

Year: 2025

Type: preprint

Abstract: 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.

Source: arXiv (Cornell University)

Authors: Kim, Dongha, Pelzman, Charles, Guo, Cheng, Long, Olivia Y., Fan, Shanhui, Cho, Sang Yeon

Institutions: Korea University, Stanford University, DEVCOM Army Research Laboratory, United States Army Combat Capabilities Development Command, The University of Texas at Austin

Language: English

Topic: Metamaterials and Metasurfaces Applications

Subfield: Electronic, Optical and Magnetic Materials

Field: Materials Science

Domain: Physical Sciences

Open Access status: green

Funders: National Research Foundation, Korea University, National Research Foundation of Korea, Multidisciplinary University Research Initiative, Army Research Office

Awards: G5394265450, G7452299184, G7663907713

OpenAlex ID: W7084446538

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