Abstract

The dynamics of electrons and spins have been measured in copper nanoparticles and nickel films by use of femtosecond pump-probe spectroscopy. In the case of copper nanoparticles embedded in glass, the thermalization of electrons in the spectral region of the plasmon mode of the metal spheres is studied with pump (60 fs)-probe (10 fs) transmission measurements. Two main observations are reported (Fig. 1): the existence of a long-lived (~500 fs) nonequilibrium electron population associated with a strong electron-electron collision regime and a slowing down of the electron-lattice relaxation at the plasmon resonance.¹ A model involving equilibrium and nonequilibrium electron populations will be discussed.

© 1996 Optical Society of America