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Maela Bazin

Control of spontaneous emission of semiconductor quantum dot inserted in microstructures with original confinement

Published on 25 June 2010


Thesis presented June 25, 2010

Abstract:
This study deals with the control of spontaneous emission, InAs quantum dot emitters, confined via original microstructures: GaAs photonic wires and micropillars with GaAs/AlAs Bragg mirrors. We present a highly efficient single-photon source based on a photonic wire. Correlation measurements performed on a single quantum dot inserted in a photonic wire led to a pure and high broadband single-photon generation. The optimization of this geometry including an original mirror at the wire bottom and a taper at its top demonstrated a record efficiency of 70%. In addition, the systematic lifetime study of single quantum dots underlined the ability to observe a high inhibition of spontaneous emission in the leaky modes with this geometry. In the last part of this PhD Thesis, we show the laser effect in whispering gallery mode micropillars. Those modes have an almost stable behavior in terms of wavelengh and a spectral narrowing maintained up to power corresponding to 7 times the laser threshold. This result confirms a better thermal stability of micropillars compared to microdisks, a geometry usually used to observe the whispering gallery modes.

Keywords:
Control of spontaneous emission, molecular beam epitaxy III-As, quantum dots, photonics wires, micropillars, single photons sources, whispering gallery modes, laser effect

On-line thesis.