Dresden 2011 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

Q: Fachverband Quantenoptik und Photonik

Q 15: Poster 1: Quanteninformation, Quanteneffekte, Laserentwicklung, Laseranwendungen, Ultrakurze Pulse, Photonik

Q 15.8: Poster

Montag, 14. März 2011, 16:30–19:30, P1

Spectroscopy and coherent control of colloidal semiconductor nanocrystals by phase-shaped femtosecond laserpulses — •Roland Wilcken, Martin Ruge, Matthias Wollenhaupt, and Thomas Baumert — University of Kassel, Institute for Physics and CINSaT, Heinrich-Plett-Str. 40, D-34132 Kassel, Germany

The interaction of a quantum system with the electric field of an ultrashort, shaped laser pulse is one of the key aspect in coherent control. Semiconductor nanocrystals - or quantum dots (QDs) - are often considered as artificial atoms with discrete energy levels but obeying bulk semiconductor properties like confined lattice vibrations as well. Several control schemes are well established for atomic and molecular transitions [1]. The aim is the adaption of control strategies based on experiences gained on atoms and molecules. The synthesis of QDs consisting of different semiconductors, e.g. PbS or CdX (X = S, Se, Te), is done by chemical hot-injection methods with the ability to tailor the size, shape and structure. In this way the optical properties can be tuned over a wide range by changing the quantum confinement. The ligand-stabilized QDs, dispersed in hexane, are used for experiments at room temperature. In a pump-probe setup collinear double pulse sequences are applied, generated by a high resolution polarization pulse shaper. The transmitted light intensity as well as the photoluminescence are detected. First results on the excitation dynamics and the related vibrational features in the nanocrystals are shown. The photoluminescence signal for a variety of different pulse shapes is measured.

[1] M. Wollenhaupt et al., Annu. Rev. Phys. Chem., 56, 25-56 (2005)