Berlin 2018 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 24: Poster Session II

HL 24.34: Poster

Tuesday, March 13, 2018, 18:30–20:30, Poster F

Photo-induced magnetic moments in nanostructered quantum rings — •Michael Kraus, Jonas Wätzel, and Jamal Berakdar — Institute for Physics, Martin-Luther-University Halle-Wittenberg, 06099 Halle (Saale), Germany

The generation of strongly focused light beams carrying orbital angular momentum (OAM) for a wide range of pulse parameters opens the door to fascinating new applications in optoelectronics and optical communications. These spatially inhomogeneous light fields allow to change the angular momentum of the sample by an amount set by the topological charge of the OAM beam which can be varied in a large range. Here we focus on nanostructured quantum rings irradiated by OAM beams inducing a substantial magnetic moment which is totally controllable by the laser parameters. Based on a full-fledged quantum simulation we investigate different laser setups to achieve the maximal magnetic moment during and after the application of the pulse. For instance, by increasing the winding number of the optical vortex the magnetic moment can be enlarged as long as the frequencies of the photo-induced electric transitions are within the bandwidth of the pulse. The irreversible relaxation processes induced by the interaction between the photoexcited electrons and acoustic phonons is included by a density matrix approach and indicates how long the generated magnetic moments are detectable.