We have developed an ultrafast, light-scattering spectroscopic system combi
ning a conventional microscope with a pump-probe setup. We successfully mea
sured the surface plasmon resonance band for the individual gold particles
with a mean radius of 40 nm. The results on the pump-probe experiment demon
strate that both the electron-phonon and the phonon-phonon coupling process
es in the individual gold particles take place with the lifetimes of 4 ps a
nd > 25 ps, respectively. (C) 2001 American Institute of Physics.