Surface collective excitations in ultrafast pump-probe spectroscopy of metal nanoparticles

Abstract

The role of surface collective excitations in the electron relaxation in small metal particles is studied. It is shown that the dynamically screened electron-electron interaction in a nanoparticle contains a size-dependent correction induced by the surface. This leads to new channels of quasiparticle scattering accompanied by the emission of surface collective excitations. In noble-metal particles, the dipole collective excitations (surface plasmons) mediate a resonant scattering of d-holes to the conduction band. The role of this effect in the ultrafast optical dynamics of small nanoparticles is studied. With decreasing nanoparticle size, it leads to a strong change in the differential absorption lineshape and a strong frequency dependence of the relaxation near the surface plasmon resonance. The experimental implications of these results in ultrafast pump-probe spectroscopy are addressed. The size-dependence of conduction electron scattering rates is also discussed.

26 pages including 10 figures. Invited paper for Special Issue of Chemical Physics on "Electron Dynamics in Metals"

References in corpus (4)

• Nonequilibrium Electron Interactions in Metal Films
• Theory of exciton-exciton correlation in nonlinear optical response
• Size-Dependent Surface Plasmon Dynamics in Metal Nanoparticles
• Canonical Transformation Approach to the Ultrafast Non-linear Optical Dynamics of Semiconductors

Cited by in corpus (6)

• Theory of plasmon-enhanced metal photoluminescence
• Response theory for time-resolved second-harmonic generation and two-photon photoemission
• Many-body Correlation Effects in the Ultrafast Nonlinear Optical Response of Confined Fermi Seas
• Hot carrier dynamics in a dispersionless plasmonic system
• Plasmonic nano-resonator enhanced one-photon luminescence from single gold nanorods
• Purcell factor for plasmon-enhanced metal photoluminescence