Joachim R. Krenn, professeur à l'Institut de physique - Universiéy de Graz, Austria donnera un séminaire intitulé

"Probing plasmons with photons and electrons"

le vendredi 29 mars à 11H en salle 774 du bâtiment Lavoisier.

Résumé :

Probing local optical fields is a major challenge in nanoscale photonics. This is particularly true for strongly confined fields, as in the case of surface plasmon modes in metal nanostructures. Besides their extreme confinement, plasmonic modes feature resonant field enhancement, ultrafast dynamics and tunable spectral selectivity. These properties have been advantageously applied in, e.g., surface enhanced molecular spectroscopy or chemistry and biosensing. While photons are the usual probe of choice for their analysis, the first experimental access to surface plasmons has been paved by electrons 60 years ago. Nowadays, electron microscopes with spectroscopic capabilities reclaim the importance of electron probes, as they combine high spatial and spectral resolution. I will discuss the close liaison of electron and photon based signals and examples for the unprecedented resolution that is provided by electron energy loss spectroscopy and cathodoluminsescence coupled to an electron microscope.