Regensburg 2013 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 60: Focus Session: Coherent dynamics in semiconductor nanostructures and coupled devices

HL 60.7: Vortrag

Mittwoch, 13. März 2013, 18:00–18:15, H16

Ultrafast dynamics of 0D/2D transitions in semiconductor DWELL structures — •Mirco Kolarczik, Nina Owschimikow, Yücel Kaptan, and Ulrike Woggon — Institut für Optik und Atomare Physik, Technische Universität Berlin, Straße des 17. Juni 135, D-10623 Berlin, Germany

We investigate 0D/2D coupling in semiconductor quantum dot (QD) in a well (DWELL) structures using heterodyne two-color pump-probe spectroscopy. In our two color pump-probe experiments we vary the pump energy from the QD ground state transition to values exceeding the quantum well (QW) band gap. Depending on the carrier population in the 2D and 3D continua created by an injection current, multiple excitation pathways are possible at a given pump laser energy. These dynamics are modelled in a fully electronic rate equation system. Including direct optical interband transitions between quantum dot and quantum well states yields excellent agreement of observed traces and the numerical model. These transitions may affect the well known intradot dynamics, especially for transition energies near the quantum well band edge, e.g. in cross gain and cross phase modulation.

To investigate coherent effects in the sub-picosecond time range, and thus obtain understanding of the complex interplay of energetically degenerate transitions, we extend the heterodyne setup to include pulse shape analysis.