SKM 2021 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 13: Poster Session III

HL 13.5: Poster

Tuesday, September 28, 2021, 13:30–16:30, P

Diameter dependent whispering gallery mode lasing effects in quantum dot micropillar cavities — •Imad Limame, Ching-Wen Shih, Johannes Pietsch, Aris Koulas-Simos, Leo Roche, and Stephan Reitzenstein — Institut für Festkörperphysik, Technische Universität Berlin, D-10623 Berlin

Whispering-gallery modes (WGMs) were first theorized by Lord Rayleigh in 1878 at the St. Paul cathedral. WGMs with lateral emission characteristics occur also in micropillar cavities which is of great interest for integrated quantum nanophotonics. In this work, we present an in depth study of WGM emission in micropillars ranging between 2 and 20 μm in diameter. The samples were grown by mean of metal organic chemical vapor deposition and include multi layers of InGaAs quantum dots as active region. The pillars were processed using electron beam lithography, using a Ni hard mask. This hard mask is only partially removed to create a highly obsorbant surface on the top of the pillar, which suppresses emission through standard vertically emitting micropillar modes. The optical properties were studied by means of micro-photoluminescence spectroscopy (μPL). Investigating the input-output characteristics, the free spectral range, the Q-factor and the beta-factor as function of the pillar diameter provides deep insight into the underlying physics and paves the way for the applicaiton of the developed WGM microlasers as coherent excitation sources in integrated quantum photonic circuits.