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Title: Quantum dot spontaneous emission control in a ridge waveguide

We investigate the spontaneous emission (SE) of self-assembled InAs quantum dots (QDs) embedded in GaAs ridge waveguides that lay on a low index substrate. In thin enough waveguides, the coupling to the fundamental guided mode is vanishingly small. A pronounced anisotropy in the coupling to non-guided modes is then directly evidenced by normal-incidence photoluminescence polarization measurements. In this regime, a measurement of the QD decay rate reveals a SE inhibition by a factor up to 4. In larger wires, which ensure an optimal transverse confinement of the fundamental guided mode, the decay rate approaches the bulk value. Building on the good agreement with theoretical predictions, we infer from calculations the fraction β of SE coupled to the fundamental guided mode for some important QD excitonic complexes. For a charged exciton (isotropic in plane optical dipole), β reaches 0.61 at maximum for an on-axis QD. In the case of a purely transverse linear optical dipole, β increases up to 0.91. This optimal configuration is achievable through the selective excitation of one of the bright neutral excitons.
Authors:
; ; ; ; ; ;  [1] ; ;  [2]
  1. CEA-CNRS-UJF group “Nanophysique et Semiconducteurs,” CEA, INAC, SP2M, F-38054 Grenoble (France)
  2. Laboratoire Photonique, Numérique et Nanosciences, Institut d'Optique d'Aquitaine, Univ. Bordeaux, CNRS, 33405 Talence, Cedex (France)
Publication Date:
OSTI Identifier:
22415173
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 4; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; EXCITONS; GALLIUM ARSENIDES; INDIUM ARSENIDES; PHOTOLUMINESCENCE; POLARIZATION; QUANTUM DOTS; SUBSTRATES; WAVEGUIDES