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HL: Fachverband Halbleiterphysik

HL 16: Microcavities

HL 16.5: Vortrag

Montag, 14. März 2011, 15:30–15:45, FOE Anorg

Whispering gallery mode lasing in electrically driven quantum dot micropillars — •Ferdinand Albert, Tristan Braun, Tobias Heindel, Christian Schneider, Stephan Reitzenstein, Sven Höfling, Lukas Worschech, and Alfred Forchel — Technische Physik and Wilhelm Conrad Röntgen Research Center for Complex Materials, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany

High quality factor and low mode volume nanophotonic devices featuring pronounced cavity quantum electrodynamics (cQED) effects are attracting considerable scientific attention with respect to efficient light sources. For instance they allow for the realization of efficient and compact microlasers. In this respect electrically driven quantum dot based micropillar lasers are of particular interest because of a straightforward current injection by a ring-shaped top contact. While standard micropillar lasers are characterized by a highly directional emission normal to the samples surface, we report on in-plane lasing emission under electrical pumping from whispering gallery modes (WGMs) confined in the central cavity layer of the micropillars. We present WGM lasing with Q-factors up to 40.000 and laser threshold currents below 10 µA. Our devices provide a significantly better heat sinking compared to standard WGM lasers based on microdisks and, thus, a better control of the emission wavelength. The latter is of particular importance for the realization of THz radiation from micropillar WGM lasers by means of difference frequency generation.