biostudies-literatureUnknown12(21)Wang RChiral metasurfaces have great potential in various applications such as polarimetric imaging and biomedical recognition. However, simultaneous broadband and high circular dichroism (CD) with high polarization extinction ratio (PER) remains a challenge. Here, we present a novel approach to realize simultaneous broadband and high CD with high PER in the optical communication band using a two-dimensional all-dielectric chiral metasurface. The structure is formed by a two-level chiral structure of split cross (first-order) and trapezoid-shaped (second-order) of Si nano ribs, respectively, in which constructively coupled first- and second-order of chirality occurs, resulting in the broad chiral response in the far field of multipoles excited by incident light of different chiralities. TheoretiNanophotonics (Berlin, Germany)4043-4053https://www.ebi.ac.uk/biostudies/studies/S-EPMC11501280biostudies-literatureSimultaneous broadband and high circular dichroism with two-dimensional all-dielectric chiral metasurface.PMC11501280Wang RWang CHu XSun TfalseSimultaneous broadband and high circular dichroism with two-dimensional all-dielectric chiral metasurface.Chiral metasurfaces have great potential in various applications such as polarimetric imaging and biomedical recognition. However, simultaneous broadband and high circular dichroism (CD) with high polarization extinction ratio (PER) remains a challenge. Here, we present a novel approach to realize simultaneous broadband and high CD with high PER in the optical communication band using a two-dimensional all-dielectric chiral metasurface. The structure is formed by a two-level chiral structure of split cross (first-order) and trapezoid-shaped (second-order) of Si nano ribs, respectively, in which constructively coupled first- and second-order of chirality occurs, resulting in the broad chiral response in the far field of multipoles excited by incident light of different chiralities. Theoreti2023-01-01T00:00:00Z2023 Oct2025-04-04T01:05:22.564Z2025-04-04T01:05:22.564ZS-EPMC115012803963564410.1515/nanoph-2023-0407