0000000000380629
AUTHOR
Olivier Soppera
Quantitative analysis of localized surface plasmons based on molecular probing
International audience; We report on the quantitative characterization of the plasmonic optical near-field of a single silver nanoparticle. Our approach relies on nanoscale molecular molding of the confined electromagnetic field by photoactivated molecules. We were able to directly image the dipolar profile of the near-field distribution with a resolution better than 10 nm and to quantify the near-field depth and its enhancement factor. A single nanoparticle spectral signature was also assessed. This quantitative characterization constitutes a prerequisite for developing nanophotonic applications.
Nanophotopolymerization Triggered by the Enhanced Optical Near Field of Metallic Nanoparticles
International audience; A novel approach is reported for imaging and quantifying both the depth and the strength of the optical near-field, of a single colloidal metal nanoparticle, associated with localized surface plasmons. It will be emphasized that this technique relies on a nanoscale molecular molding of the confined electromagnetic field of metal colloids, irradiated at their resonance, by a photo-activated polymer, which enabled us to directly image the dipolar profile of the near-field distribution with an unprecedented resolution, better than 10 nm. Moreover, the approach used enabled one to quantify the near-field enhancement factor. This approach has overcome all the difficulties…
Plasmon-based free-radical photopolymerization : effect of diffusion on nanolithography processes
This Article interrogates the mechanisms responsible for nanoscale photopolymerization induced by confined and enhanced electromagnetic fields. Surface plasmon dipolar resonance of individual Ag nanoparticles was used as an optical near-field source to locally trigger the reaction of a photopolymerizable formulation. Laser excitation of the nanoparticles embedded in the formulation reproducibly generates polymer features with typical dimensions ranging from 2 nm to a few tens of nanometer. We have determined the physicochemical parameters and mechanisms controlling the spatial extent of the photopolymerization process. We found that the diffusion of the dye is the main process limiting the …
Off-Resonant Optical Excitation of Gold Nanorods: Nanoscale Imprint of Polarization Surface Charge Distribution
International audience; We report on the nanoscale optical characterization of gold nanorods irradiated out of their plasmonic resonance. Our approach is based on the reticulation of a photopolymerizable formulation locally triggered by enhanced electromagnetic fields. The tiny local field enhancement stems from the surface polarization charges associated with the electric field discontinuity at the metal/dielectric interface. This allows us to get a nanoscale signature of the spatial distribution of the surface charge density in metallic nanoparticles irradiated off-resonance.