Berlin 2018 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 46: Quantum dots and wires: Optical properties III

HL 46.2: Talk

Thursday, March 15, 2018, 15:15–15:30, A 151

White light coherent 2D-spectroscopy on electrically pumped semiconductor nanostructures — Mirco Kolarczik, •Kevin Thommes, Bastian Herzog, Sophia Helmrich, Nina Owschimikow, and Ulrike Woggon — Institut für Optik und Atomare Physik, Technische Universität Berlin, Germany

InAs/GaAs nanostructures are an established material system for the fabrication of opto-electronic devices. Coherent and incoherent coupling mechanisms between the subsystems of different dimensionality (3D, 2D, and 0D) are the backbone of their functionality. We developed a setup for collinear two-dimensional coherent spectroscopy based on broadband laser pulses from a fiber laser system to address the complexity of such active media under operating conditions. We investigate Stranski-Krastanov grown InAs quantum dots in an InGaAs quantum well forming the active medium in the waveguide structure of a semiconductor optical amplifier. This device allows to control the inversion state of the optical transitions by electrical carrier injection. We observe the evolution of the homogeneous linewidth of the optical transitions in the inhomogeneously broadened quantum dot ensemble under variation of the initial inversion. Additionally, our broadband laser pulses allow us to observe coherent coupling of the quantum dot ground state and excited state separated by 70 meV.