Selective Enhancement of Optical Chirality and Spin Angular Momentum in Plasmonic Near-Field
arXiv:2505.19878 · doi:10.1021/acs.nanolett.5c02776
Abstract
The interaction between circularly polarized (CP) light and matter is governed by two fundamental quantities: spin angular momentum (SAM) and optical chirality (OC). While these quantities are inseparable in free space, they can be selectively enhanced in plasmonic near-field regions through appropriately designed structures. We demonstrate that the excitation of circular plasmonic nanostructures with CP light enables selective or simultaneous enhancement of SAM and OC through the excitation of rotating plasmon modes. Electromagnetic field analysis reveals that SAM enhancement originates from transverse SAM induced by unidirectional evanescent waves, whereas OC enhancement is governed by the interference between the plasmonic electric field and incident magnetic field. The finite element method simulations confirm that circular dichroism signals arising from these enhanced near fields clearly depend on the SAM and OC of the local fields, underscoring the importance of structural design in the detection and enhancement of optically active phenomena at the nanoscale.
11 pages, 6 figures
References in corpus (14)
- Extraordinary momentum and spin in evanescent waves
- Circuit elements at optical frequencies: nano-inductors, nano-capacitors and nano-resistors
- Does a Surface Polariton Have Spin?
- Characterizing optical chirality
- Surface enhanced circular dichroism spectroscopy mediated by non-chiral nanoantennas
- Chirality and angular momentum in optical radiation
- Transverse spin dynamics of light: the generalized spin-momentum locking for structured guided modes
- Compact electric-LC resonators for metamaterials
- Spin-Momentum Locking in the Near Field of Metal Nanoparticles
- Molecular-Induced Chirality Transfer to Plasmonic Lattice Modes
- Spin angular momentum and optical chirality of Poincaré vector vortex beams
- Transverse spin angular momentum of space-time surface plasmon polariton wave packet
- Rotationally displaced electric field intensity distribution around square nanoantennas induced by circularly polarized light
- Designing rotational motion of charges on plasmonic nanostructures excited by circularly polarized light