Femtosecond formation of coupled phonon-plasmon modes in InP: Ultrabroadband THz experiment and quantum kinetic theory.
The ultrafast transition of an optical phonon resonance to a coupled phonon-plasmon system is studied. After 10-fs photoexcitation of i-InP, the buildup of coherent beats of the emerging hybrid modes is directly monitored via ultrabroadband THz spectroscopy. The anticrossing is mapped out as a function of time and density. A quantum kinetic theory of microscopic carrier-carrier and carrier-LO-phonon interactions explains the delayed formation of the collective modes. The buildup time is quantitatively reproduced to scale with the oscillation cycle of the upper branch of the coupled resonance.
Huber
R
R
Physik-Department E11, Technische Universität München, D-85748 Garching, Germany.
Kübler
C
C
Tübel
S
S
Leitenstorfer
A
A
Vu
Q T
QT
Haug
H
H
Köhler
F
F
Amann
M-C
MC