(1) LASIM, CNRS, Université Lyon 1, 43 boulevard du 11 novembre 1918, 69622 Villeurbanne, France;(2) CPMOH, CNRS, Université Bordeaux 1, 351 cours de la Liberation, 33405 Talence, France
Abstract:
The extinction spectrum of single silver nanoparticles
with size ranging from 20 to 80 nm is investigated with the spatial
modulation spectroscopy technique using either a tunable laser or a white
lamp as the broadband source. Results are in good agreement with the
prediction of the Mie theory, permitting to extract the nanoparticle size
from the measured absolute value of the optical extinction cross-section. In
contrast, the deduced refractive index of the nanoparticle environment and
the reduction of the electron mean free path show a large dependence on the
precise value of the bulk silver dielectric function.