2026-05-05T21:10:17Zhttps://uvadoc.uva.es/oai/request

oai:uvadoc.uva.es:10324/750662025-02-17T20:00:52Zcom_10324_1158com_10324_931com_10324_894col_10324_1242

Superchiral light emerging from bound states in the continuum in metasurfaces of Si nanorod dimers Pura Ruiz, José Luis Castillo López de Larrinzar, Beatriz Liang, Minpeng García Martín, Antonio Gómez Rivas, Jaime Sánchez Gil, José A. Producción Científica Bound states in the continuum (BICs) in all-dielectric metasurfaces enhance light–matter interaction at the nanoscale due to their infinite Q factors and strong field confinement. Among a variety of phenomena already reported, their impact on chiral light has recently attracted great interest. Here we investigate the emergence of intrinsic and extrinsic optical chirality associated with the excitation of BICs in various metasurfaces made of Si nanorod dimers on a quartz substrate, comparing three cases: parallel nanorods (neutral) and shifted and slanted dimers, with/without index-matching superstrate. We analyze both the circular dichroism (CD) of the far-field (FF) interaction and the helicity of the near-field (NF) distribution. We show that the best approach to achieve chiral response in the FF based on extrinsic chirality is to exploit quasi-BICs (q-BICs) appearing in the case of slanted nanorod dimers. By contrast, the helicity density is largely enhanced in the case of shifted dimers, as it presents intrinsic chirality, with values 2 orders of magnitude larger than those of circularly polarized plane waves. These so-called superchiral electromagnetic fields concentrated at the nanoscale within the metasurface hold promise of appealing implications in phenomena such as strong-coupling, photoluminescence emission, or other local light–matter interactions. 2025-02-17T11:26:06Z 2025-02-17T11:26:06Z 2024 info:eu-repo/semantics/article ACS Photonics, 2024, vol. 11, n. 10, p. 4090-4100 2330-4022 https://uvadoc.uva.es/handle/10324/75066 10.1021/acsphotonics.4c00938 4090 10 4100 ACS Photonics 11 2330-4022 eng https://pubs.acs.org/doi/10.1021/acsphotonics.4c00938 info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/4.0/ © 2024 The Authors Atribución 4.0 Internacional ACS (American Chemical Society) SI