TY - BOOK

T1 - Efficient fiber-coupled single-photon sources based on quantum dots

AU - Daveau, Raphaël Sura

PY - 2016

Y1 - 2016

N2 - This thesis presents the study of solid-state quantum emitters in two dierent forms. Therst part of the thesis deals with quantum dot based single-photon sources with an emphasison ecient photon extraction into an optical ber. The second part of the thesis covers atheoretical study of optical refrigeration with coupled quantum wells.Many photonic quantum information processing applications would benet from a highbrightness,ber-coupled source of triggered single photons. This thesis presents a studyof such sources based on quantum dots coupled to unidirectional photonic-crystal waveguidedevices, where the out-coupling section of the device is separated from the strongemitter-waveguide coupling section. Two out-coupling methods are investigated. The rstmethod, end-re coupling from a tapered waveguide to a lensed ber, yields a chip-to-bercoupling eciency of 16.6 %, which is calculated through the characterization of singlequantum dots. The second method, evanescent coupling from a tapered waveguide to amicrober, demonstrates a chip-to-ber coupling eciency exceeding 80 % in passive re-ection measurements. The characterization of quantum dots from this device establishesa ber-coupled source eciency of 15.6 %. This latter method opens a promising futurefor increasing the eciency and reliability of planar chip-based single-photon sources.Refrigeration of a solid-state system with light has potential applications for coolingsmall-scale electronic and photonic circuits. We show theoretically that two coupledsemiconductor quantum wells are ecient cooling media because they support long-livedindirect electron-hole pairs. These pairs can be thermally excited to distinct higher-energystates with faster radiative recombination, thereby creating an ecient escape channel toremove thermal energy from the system. From band-diagram calculations along with anexperimentally realistic level scheme we calculate the cooling eciency and cooling yieldof dierent devices with coupled quantum wells embedded in a suspended nanomembrane

AB - This thesis presents the study of solid-state quantum emitters in two dierent forms. Therst part of the thesis deals with quantum dot based single-photon sources with an emphasison ecient photon extraction into an optical ber. The second part of the thesis covers atheoretical study of optical refrigeration with coupled quantum wells.Many photonic quantum information processing applications would benet from a highbrightness,ber-coupled source of triggered single photons. This thesis presents a studyof such sources based on quantum dots coupled to unidirectional photonic-crystal waveguidedevices, where the out-coupling section of the device is separated from the strongemitter-waveguide coupling section. Two out-coupling methods are investigated. The rstmethod, end-re coupling from a tapered waveguide to a lensed ber, yields a chip-to-bercoupling eciency of 16.6 %, which is calculated through the characterization of singlequantum dots. The second method, evanescent coupling from a tapered waveguide to amicrober, demonstrates a chip-to-ber coupling eciency exceeding 80 % in passive re-ection measurements. The characterization of quantum dots from this device establishesa ber-coupled source eciency of 15.6 %. This latter method opens a promising futurefor increasing the eciency and reliability of planar chip-based single-photon sources.Refrigeration of a solid-state system with light has potential applications for coolingsmall-scale electronic and photonic circuits. We show theoretically that two coupledsemiconductor quantum wells are ecient cooling media because they support long-livedindirect electron-hole pairs. These pairs can be thermally excited to distinct higher-energystates with faster radiative recombination, thereby creating an ecient escape channel toremove thermal energy from the system. From band-diagram calculations along with anexperimentally realistic level scheme we calculate the cooling eciency and cooling yieldof dierent devices with coupled quantum wells embedded in a suspended nanomembrane

UR - https://soeg.kb.dk/permalink/45KBDK_KGL/fbp0ps/alma99122193244305763

M3 - Ph.D. thesis

BT - Efficient fiber-coupled single-photon sources based on quantum dots

PB - The Niels Bohr Institute, Faculty of Science, University of Copenhagen

ER -