Seminars Archive

Plasmon Resonance Dynamics of Silver Triangular Nanoplates by Ultrafast Pump-Probe Spectroscopy

Abstract
The short-time optical response of metal involves the excitation-relaxation dynamics of electrons, plasmons and phonons. In nanoparticles, these dynamics are further modified by confinement and by the interplay between bulk and surface effects. We have investigated the ultrafast dynamics that follows impulsive laser excitation of triangular silver nano-plates in aqueous solution. The particles growth is driven by a photochemical reaction that allows controlling the size and shape of the products. We use multicolor transient absorption spectroscopy to capture the complex dynamics of these particles and isolate the processes that contribute to it, on different time-scales, ranging from tens of fs to hundreds of ps. We use model calculations to interpret the results and gain new insight on the behaviour of electrons and phonons in confined systems interacting with their environment.