SANDiE Partner P20

Universität Dortmund, Germany

The scientific contribution of the team of the University of Dortmund (U. Woggon) to SANDiE is focussed on JPR 10 (Long wavelength) and JPR 13 (Novel SAN). We experimentally investigate epitaxally-grown QD amplifiers under optical and electrical injection, with emission in the infrared region (1.17 - 1.3 µm). The devices are In(Ga)As QDs embedded in a ridge waveguide structure with AlGaAs cladding layers. We investigate the ultrafast gain and refractive index dynamics and the homogeneous linewidth of the electronic states in the QDs using pump-probe and four-wave-mixing experiments in heterodyne detection scheme. We investigate the ultrafast gain and refractive index dynamics and the homogeneous linewidth of the electronic states in the QDs using a pump-probe and four-wave-mixing experiment in heterodyne detection scheme.

Recently we started spectroscopic studies of 1D-nanostructures such as nanorods, or quantum wires. The quantum-nature of the emitting state in a 1D-nanostructure is of fundamental interest and subject of our contribution to the NoE Sandie. Since the size-dependent 1D-exciton fine structure defines the eigenstate symmetry, the oscillator strength and the level structure of the exciton ground state, a detailed understanding of this size dependence is crucial for defining threshold conditions in nanowire-lasers, quantum optics, and in polarization sensitive marking and detecting devices.

The Dortmund team provides access to advanced spectroscopic techniques: Time resolved spectroscopy of nanostructures. Techniques with resolution from ~0.1ps upwards allow the dynamical properties of nanostructures to be probed. Ultra-fast pump-probe and four wave mixing measurements. Micro-photoluminescence at varying temperature, Temperature-dependent linewidth-enhancement factor (LEF).

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last update: 28 February 2019, A. Weber