Coherent nonlinear optical response of single quantum dots studied by ultrafast near-field spectroscopy.
The nonlinear response of single GaAs quantum dots is studied in femtosecond near-field pump-probe experiments. At negative time delays, transient reflectivity spectra show pronounced oscillatory structure around the quantum dot exciton line, providing the first evidence for a perturbed free induction decay of the excitonic polarization. Phase-disturbing Coulomb interactions between the excitonic polarization and continuum excitations dominate the optical nonlinearity on ultrafast time scales. A theoretical analysis based on the semiconductor Bloch equations accounts for this behavior.
Guenther
Tobias
T
Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, D-12489 Berlin, Germany.
Lienau
Christoph
C
Elsaesser
Thomas
T
Glanemann
Markus
M
Axt
Vollrath Martin
VM
Kuhn
Tilmann
T
Eshlaghi
Soheyla
S
Wieck
Andreas D
AD