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Nitin Singh Malik

Photonic nanowires: A new geometry to realize bright sources of quantum light

Published on 21 November 2011


Thesis presented November 21, 2011

Abstract:
This thesis presents the realization of an efficient single-photon source based on an InAs quantum dot integrated in a photonic nanowire. A photonic nanowire is a mono mode waveguide made of a high refractive index material (GaAs in our case). For an optimal wire diameter around 200 nm, nearly all the spontaneous emission of the embedded single-photon emitter (free space wavelength ~950 nm) is funneled into the fundamental guided mode. In addition, the out coupling efficiency of the guided photon to a microscope objective can be brought close to one with a proper engineering of the wire ends. The source thus features an integrated bottom mirror and a smooth tapering of the wire upper end. High performances are maintained over a broad wavelength range, a key asset of this 1D photonic structure. This thesis presents the physics which governs these structures, their realization, and their characterization. Under pulsed optical pumping, we demonstrate a single-photon source with a record efficiency of 0.72, combined with highly pure single-photon emission. We also discuss the possibility to obtain polarization control, using wire with an elliptical section.

Keywords:
Quantum light, Quantum dot, III-V Semiconductors, Photonic nanowires, Nanophotonics

On-line thesis.