Selective excitation of nanoparticle vibrations due to plasmon tuning

We investigate the vibrational modes of metal nanoparticles, and their interaction with their environment. To that end, we use pump-probe transmission measurements. The laser can be tuned to the plasmon of either the isolated particles or the interacting particles, which changes the excited and observed population.

In particular, this selective excitation was used to study gold nanoparticles deposited on a polyelectrolyte monolayer on glass, and we found we could distinguish monomer from dimer vibrational modes. Furthermore, the selectivity meant that the vibrational modes had a quality factor higher than expected from the size dispersion.