Pyramidal quantum dots: single and entangled photon sources and correlation studies

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dc.check.embargoformatE-thesis on CORA onlyen
dc.check.entireThesisEntire Thesis Restricted
dc.check.opt-outNoen
dc.check.reasonThis thesis is due for publication or the author is actively seeking to publish this materialen
dc.contributor.advisorPelucchi, Emanueleen
dc.contributor.authorJuska, Gediminas
dc.contributor.funderScience Foundation Irelanden
dc.date.accessioned2014-02-17T14:41:11Z
dc.date.available2015-02-18T05:00:05Z
dc.date.issued2013
dc.date.submitted2013
dc.description.abstractPractical realisation of quantum information science is a challenge being addressed by researchers employing various technologies. One of them is based on quantum dots (QD), usually referred to as artificial atoms. Being capable to emit single and polarization entangled photons, they are attractive as sources of quantum bits (qubits) which can be relatively easily integrated into photonic circuits using conventional semiconductor technologies. However, the dominant self-assembled QD systems suffer from asymmetry related problems which modify the energetic structure. The main issue is the degeneracy lifting (the fine-structure splitting, FSS) of an optically allowed neutral exciton state which participates in a polarization-entanglement realisation scheme. The FSS complicates polarization-entanglement detection unless a particular FSS manipulation technique is utilized to reduce it to vanishing values, or a careful selection of intrinsically good candidates from the vast number of QDs is carried out, preventing the possibility of constructing vast arrays of emitters on the same sample. In this work, site-controlled InGaAs QDs grown on (111)B oriented GaAs substrates prepatterned with 7.5 μm pitch tetrahedrons were studied in order to overcome QD asymmetry related problems. By exploiting an intrinsically high rotational symmetry, pyramidal QDs were shown as polarization-entangled photon sources emitting photons with the fidelity of the expected maximally entangled state as high as 0.721. It is the first site-controlled QD system of entangled photon emitters. Moreover, the density of such emitters was found to be as high as 15% in some areas: the density much higher than in any other QD system. The associated physical phenomena (e.g., carrier dynamic, QD energetic structure) were studied, as well, by different techniques: photon correlation spectroscopy, polarization-resolved microphotoluminescence and magneto-photoluminescence.en
dc.description.statusNot peer revieweden
dc.description.versionAccepted Version
dc.format.mimetypeapplication/pdfen
dc.identifier.citationJuska, G. 2013. Pyramidal quantum dots: single and entangled photon sources and correlation studies. PhD Thesis, University College Cork.en
dc.identifier.endpage121
dc.identifier.urihttps://hdl.handle.net/10468/1389
dc.language.isoenen
dc.publisherUniversity College Corken
dc.rights© 2013, Gediminas Juska.en
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/3.0/en
dc.subjectQuantum dotsen
dc.subjectPolarization-entangled photonsen
dc.subject.lcshQuantum theoryen
dc.subject.lcshPhotonsen
dc.thesis.opt-outfalse
dc.titlePyramidal quantum dots: single and entangled photon sources and correlation studiesen
dc.typeDoctoral thesisen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnamePhD (Science)en
ucc.workflow.supervisoremanuele.pelucchi@tyndall.ie
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