Extreme Optical Chirality from Plasmonic Nanocrystals on a Mirror.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39804126.
- Also identified by DOI 10.1021/acs.nanolett.4c05668 and PMC identifier 11760171.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Metal nanocrystals synthesized in achiral environments usually exhibit no chiroptical effects. However, by placing nominally achiral nanocrystals 1.3 nm above gold films, we find giant chiroptical effects, reaching anisotropy factors as high as <i>g</i> ≈ 0.9 for single nanodecahedra placed on a gold mirror (NDoM). We show that this is a general phenomenon depending on the geometry, demonstrating it for various nanocrystal shapes. Theoretical modeling reveals that tiny chiral imperfections are strongly enhanced by edge modes in the gap, which coherently superpose with in-plane dipoles to generate strong chiroptical signatures. This phenomenon results in photonic spin Hall effects and distinctive chiral scattering patterns.