17 research outputs found
Improving the performance of bright quantum dot single photon sources using amplitude modulation
Single epitaxially-grown semiconductor quantum dots have great potential as
single photon sources for photonic quantum technologies, though in practice
devices often exhibit non-ideal behavior. Here, we demonstrate that amplitude
modulation can improve the performance of quantum-dot-based sources. Starting
with a bright source consisting of a single quantum dot in a fiber-coupled
microdisk cavity, we use synchronized amplitude modulation to temporally filter
the emitted light. We observe that the single photon purity, temporal overlap
between successive emission events, and indistinguishability can be greatly
improved with this technique. As this method can be applied to any triggered
single photon source, independent of geometry and after device fabrication, it
is a flexible approach to improve the performance of solid-state systems, which
often suffer from excess dephasing and multi-photon background emission
Properties of a single photon generated by a solid-state emitter: effects of pure dephasing
We investigate the properties of a single photon generated by a solid-state
emitter subject to strong pure dephasing. We employ a model in which all the
elements of the system, including the propagating fields, are treated quantum
mechanically. We analytically derive the density matrix of the emitted photon,
which contains full information about the photon, such as its pulse profile,
power spectrum, and purity. We visualize these analytical results using
realistic parameters and reveal the conditions for maximizing the purity of
generated photons.Comment: 25pages(one column), 10 figure
Generation of non-classical light by single quantum dots
The emission statistics of single semiconductor quantum dots is investigated in view of generating quantum states of light. Correlation experiments show that the emission of a quantum dot can be regulated so as to produce only one photon at a time as well as correlated photon pairs. This observation opens the way to the use of semiconductor quantum dots as triggered sources of single photons, which could find applications in quantum cryptography. We then discuss the potentiality of quantum dots for the production of mutually coherent single photons as well as entangled photons that could be used in quantum information processing schemes. © 2002 Elsevier Science B.V. All rights reserved
Photons indiscernables : qui se ressemble, s'assemble
Les boîtes quantiques semi-conductrices sont
des candidats prometteurs pour la génération d'états quantiques
de la lumière, tels que des photons uniques. En isolant ces
nano-émetteurs dans des microcavités optiques, ces émetteurs
uniques peuvent produire des photons identiques : l'exaltation du taux
d'émission spontanée permet de contourner les effets de perte de
cohérence de l'émetteur, qui marquent aléatoirement les photons
émis. L'indiscernabilité entre photons est sondée via des
expériences d'interférence à deux photons. La visibilité du
processus d'interférence indique des taux d'indiscernabilité
supérieurs à 70% entre photons émis par une boîte
isolée en cavité micropilier ou à cristal photonique
Single photon emission from individual semiconductor nanostructures
The correlation between the photons emitted by an optically pumped single quantum dot is investigated. The correlation function on a single dot isolated in a mesa shows that only one photon is emitted at a time at the exciton frequency. These quantum states of light can be generated with a high quantum efficiency, with the use of cavity effects: surrounding the dot by a pillar microcavity not only increases significantly the single photon flux but also allows the preparation of single photons all in the same quantum state (same spatial mode and same polarization). © 2002 Published by Elsevier Science B.V
Photons uniques indiscernables à partir d'une boîte quantique unique dans un cristal photonique
Nous avons développé et caractérisé une source de
photons uniques basée sur l'émission spontanée d'une
boîte quantique unique insérée dans une cavité
à bande interdite photonique bidimensionnelle. Ce système
nous a d'abord permis de produire des photons uniques, puis des
photons uniques indiscernables avec une indiscernabilité
supérieure à 70%. L'observation de l'indiscernabilité
des photons, impossible sans un raccourcissement important de la
durée de vie, met en évidence un effet Purcell supérieur
à 25 dans ce système