Observation of hot-electron pressure in the vibration dynamics of metal nanoparticles
We investigate the vibration dynamics of ellipsoidal silver nanoparticles, using time-resolved optical pump-probe spectroscopy. When excited with femtosecond laser pulses, the particles execute anisotropic shape oscillations. We show that these vibrations are triggered by the thermal expansion of the optically heated particles. The time dependence of the vibrations indicates that this expansion is caused by two mechanisms: The lattice anharmonicity and the extremely large pressure of the hot conduction electrons.
Perner
M
Lehrstuhl fur Photonik und Optoelektronik, Sektion Physik and CeNS, Ludwig-Maximilians-Universitat Munchen, Amalienstrasse 54, D-80799 Munchen, Germany.
Gresillon
S
Marz
J
von Plessen G
Feldmann
J
Porstendorfer
J
Berg
K
Berg
G