Dresden 2011 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 70: Quantum Dots and Wires: Theory

HL 70.8: Vortrag

Donnerstag, 17. März 2011, 12:15–12:30, POT 151

Reduction of the modulation bandwidth for high carrier scattering in semiconductor QD based laser devices — •Michael Lorke, Torben R. Nielsen, and Jesper Mørk — DTU Fotonik, Department of Photonics Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark

Semiconductor lasers are central components of current optical technologies such as optical data storage and optical communications. To meet the continuously increasing need for progressively higher data transmission rates, a high modulation bandwidth of the underlying semiconductor device is required. The combination of quantum dots (QDs) with high-quality cavities, e.g. realized by photonic crystals, opens a multitude of possibilities for guiding and modifying the emission properties of QD-based devices via the Purcell effect.

We apply a microscopic theory to study dynamical properties of QD based nanocavity devices. Application relevant quantities such the modulation bandwidth as well as fundamental properties such as the laser linewidth and switch-on behavior are determined consistently from a microscopic semiconductor approach. Our theory predicts a reduction of the modulation bandwidth at high scattering rate allowing for optimization of QD based nanocavity devices. This behavior arises from a delicate balancing of the emission time and the photon lifetime in the cavity, as both the relaxation oscillation frequency and the damping of the relaxation oscillations grow with faster scattering.