Berlin 2024 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 37: Poster IV

HL 37.16: Poster

Wednesday, March 20, 2024, 18:00–20:30, Poster F

High-β lasing in photonic-defect semiconductor-dielectric hybrid microresonators with embedded InGaAs quantum dots — •Kartik Gaur, Ching-Wen Shih, Imad Limame, Aris Koulas-Simos, Niels Heermeier, Chirag Palekar, Sarthak Tripathi, Sven Rodt, and Stephan Reitzenstein — Institut für Festkörperphysik, Technische Universität Berlin, D-10623 Berlin

InGaAs quantum dots embedded in microcavities based on highly reflective distributed Bragg reflectors (DBRs) allow for the development of high Q-factor, low mode volume microcavities that feature high light-matter interaction. However, epitaxially grown DBRs consisting of GaAs/AlAs layers suffer from relatively low refractive index contrast, and often high absorption of the laser light upon optical pumping. Here, we propose an easy-to-fabricate microcavity design to produce optically pumped high-β quantum dot microlasers. Our cavity concept is based on a buried photonic defect for tight lateral mode confinement in a quasi-planar microcavity system, which includes an upper dielectric DBR as a promising alternative to conventional III-V semiconductor DBRs. The cavities show distinct emission features with a characteristic photonic defect size-dependent mode separation and Q-factors up to 17000. Comprehensive investigations further reveal lasing operation with a systematic increase (decrease) of the β-factor (threshold pump power) with the number of mirror pairs in the upper dielectric DBR. Notably, due to the quasi-planar device geometry, the microlasers show high temperature stability.

Keywords: quantum dots; epitaxy; quantum dot laser; photonic defect