Dresden 2006 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 9: Poster I

HL 9.67: Poster

Montag, 27. März 2006, 15:15–17:45, P3

Control of occupations and coherences in semiconductor quantum dots induced by traveling wave packets — •Doris Reiter, Vollrath Martin Axt, and Tilmann Kuhn — Institut für Festkörpertheorie, Westfälische Wihelms-Universität Münster, Wilhelm-Klemm-Str.10, 48145 Münster, Germany

The capture of a traveling electronic wave packet by carrier-phonon interaction from a semiconductor quantum wire into a quantum dot can result in a superpostion of the discrete dot states. We show that we can control not only the resulting occupations but also the coherences between the discrete dot states by suitably creating two wave packets. By varying the starting time, starting position or the mean excess energy of the wave packets we achieve different control mechanism. While usually coherences are controlled directly by optical methods, in our case a decisive element of control is the arrival time of the wave packets at the dot. When we place two wave packets at each side of the dot the two packets cannot interfere, so we can easily control the time difference of the arrival by the starting time or starting position of the wave packets. If we generate two packets at the same side of the dot interference leads to spectral shaping of the pulses, which has great influence on both occupations and coherences. Another interesting case is the excitation with multicolor pulses, where we can address selectively the discrete dot states. More interestingly, we can gain control over the coherences in this case.