Circular polarization conversion in single plasmonic spherical particles
Temporal and spectral behaviors of plasmons determine their ability to enhance the characteristics of metamaterials tailored to a wide range of applications, including electric-field enhancement, hot-electron injection, sensing, as well as polarization and angular momentum manipulation. We report a dark-field (DF) polarimetry experiment on single particles with incident circularly polarized light in which gold nanoparticles scatter with opposite handedness at visible wavelengths. Remarkably, for silvered nanoporous silica microparticles, the handedness conversion occurs at longer visible wavelengths, only after adsorption of molecules on the silver. Finite element analysis (FEA) allows matching the circular polarization (CP) conversion to dominant quadrupolar contributions, determined by the specimen size and complex susceptibility. We hypothesize that the damping accompanying the adsorption of molecules on the nanostructured silver facilitates the CP conversion. These results offer new perspectives in molecule sensing and materials tunability for light polarization conversion and control of light spin angular momentum at submicroscopic scale.
Funding
Nonlinear optical micro-spectroscopy for multiplex suspension immunoassay
Science Foundation Ireland
Find out more...Electrically pumped all-inorganic LEDs and lasers by colloidal nanorod heterogeneous assembly
Science Foundation Ireland
Find out more...History
Publication
Nano Letters. 22, 4, pp.1504–1510Publisher
American Chemical SocietyOther Funding information
Irish Research Council GOIPD/2018/716Also affiliated with
- Bernal Institute
External identifier
Department or School
- Physics