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Lecture Atac Imamoglu


18 april 2006 FWN-Building 5111.0080, Nijenborgh 4, 9747 AG, Groningen
Speaker:Prof. Atac Imamoglu
Affiliation:Quantum Photonics Group at ETH Zurich
Title:Spin manipulation in quantum dots
Date:Tue Apr 18, 2006
Location:FWN-Building 5111.0080
Host:Caspar van der Wal
Telephone:+31 50 363 4555 / 4974 (secr.)


In this presentation we will discuss the basic physics behind THz generation and detection using femtosecond laser pulses, as well as the novel experiments performed on the semiconductor nanostructures. Ultrafast polarization dynamics in an optically pumped internally biased piezoelectric InGaN/GaN quantum well (QW) structure will be studied using THz emission spectroscopy. It will be shown that the bias electric field on the order of MV/cm in such a QW can be completely screened by the optically excited carriers on a time scale shorter than the laser pump pulse duration. Such an optically induced screening is a very nonlinear process and strongly influences both optical and electronic properties of the sample. We will also discuss the ultrafast carrier dynamics in Stranski-Krastanow grown InAs/GaAs quantum dot (QD) structure studied in an optical-pump THz-probe experiment. It will be shown that the presence of QDs significantly reduces the free-carrier lifetime due to efficient trapping process, still keeping the carrier mobility high, thus making such structures potentially promising for ultrafast optoelectronics.
Laatst gewijzigd:22 oktober 2012 14:31