Size dependence of the wavefunction of self-assembled InAs quantum dots from time-resolved optical measurements

Johansen, Jeppe; Stobbe, Søren; Nikolaev, Ivan S.; Lund-Hansen, Toke; Kristensen, Philip Trøst; Hvam, Jørn Märcher; Vos, Willem L.; Lodahl, Peter

doi:10.1103/physrevb.77.073303

Cited by 131 publications

(166 citation statements)

References 25 publications

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“…Our measurements are performed on an ensemble of quantum dots that are randomly oriented with respect to the interface. This situation differs from self-assembled dots that are strongly oriented [18]. A decay measurement f (t)…”

Section: B Model Of Decay Ratesmentioning

confidence: 99%

“…Recently it has been found that the emission oscillator strength can also be determined with this technique [18]. Here, we place CdSe quantum dots on different distances near a silver interface to quantitatively determine the oscillator strength as a function of emission energy.…”

Section: Introductionmentioning

confidence: 99%

“…The emission rate will be affected by emission which is reflected at the interface and leads to a controlled modification of the local density of states (LDOS) allowing us to separate radiative and nonradiative decay rate components. This technique has been pioneered by Drexhage for dye molecules [15] and used to determine quantum efficiency of Si nanocrystals [16], erbium ions [17], epitaxially grown InAs quantum dots [18] and colloidal CdSe quantum dots [19,20].…”

Section: Introductionmentioning

confidence: 99%

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Size-dependent oscillator strength and quantum efficiency of CdSe quantum dots controlled via the local density of states

et al. 2009

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We study experimentally time-resolved emission of CdSe quantum dots in an environment with a controlled local density of states (LDOS). The decay rate is measured versus frequency and as a function of distance to a mirror. We observe a linear relation between the decay rate and the LDOS, allowing us to determine the size-dependent quantum efficiency and oscillator strength. We find that the quantum efficiency decreases with increasing emission energy mostly due to an increase in nonradiative decay. For the first time, we manage to obtain the oscillator strength of the important class of CdSe quantum dots. The oscillator strength varies weakly with frequency in agreement with behavior of quantum dots in the strong confinement limit. Surprisingly, the measured absolute values are a factor of 5 below theoretically calculated values. Our results are relevant for applications of CdSe quantum dots in spontaneous emission control and cavity quantum electrodynamics. * URL: www.photonicbandgaps.com arXiv:0808.3191v1 [physics.optics]

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Section: B Model Of Decay Ratesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Size-dependent oscillator strength and quantum efficiency of CdSe quantum dots controlled via the local density of states

et al. 2009

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“…It should be noted that the effect of variations in the LDOS will be less pronounced in the mean decay time than in the purely radiative decay time since the former also includes contributions from nonradiative decay, which is unaffected by the LDOS. 12 The experimental variations in the mean decay times are thus expected to be a conservative estimate of the actual LDOS variations in the PCM.…”

Section: Decay Dynamics Of Quantum Dots Influenced By the Local Densimentioning

confidence: 99%

Decay dynamics of quantum dots influenced by the local density of optical states of two-dimensional photonic crystal membranes

Julsgaard

Johansen

Stobbe

et al. 2008

Applied Physics Letters

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We have performed time-resolved spectroscopy on InAs quantum dot ensembles in photonic crystal membranes. The influence of the photonic crystal is investigated by varying the lattice constant systematically. We observe a strong slow down of the quantum dots' spontaneous emission rates as the two-dimensional bandgap is tuned through their emission frequencies. The measured band edges are in full agreement with theoretical predictions. We characterize the multi-exponential decay curves by their mean decay time and find enhancement of the spontaneous emission at the bandgap edges and strong inhibition inside the bandgap in good agreement with local density of states calculations.

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“…Semiconductor quantum dots are very promising solid-state single-photon sources 3,4 thanks to their quantized energy levels, high optical quantum efficiency, 5 and coherent emission properties. 6 The harvesting of the emitted photons into a single mode is typically achieved by placing the emitters within a photonic nanostructure, such as a resonant cavity 7 or a broadband light collector like a PhC waveguide 8 or a nanowire.…”

mentioning

confidence: 99%

Extraction of the β-factor for single quantum dots coupled to a photonic crystal waveguide

Thyrrestrup

Sapienza

Lodahl

2010

Applied Physics Letters

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We present measurements of the β-factor, describing the coupling efficiency of light emitted by single InAs/GaAs semiconductor quantum dots into a photonic crystal waveguide mode. The β-factor is evaluated by means of time-resolved frequency-dependent photoluminescence spectroscopy. The emission wavelength of single quantum dots is temperature tuned across the band edge of a photonic crystal waveguide and the spontaneous emission rate is recorded. Decay rates up to 5.7 ns −1 , corresponding to a Purcell factor of 5.2, are measured and β-factors up to 85% are extracted. These results prove the potential of photonic crystal waveguides in the realization of on-chip single-photon sources.

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Size dependence of the wavefunction of self-assembled InAs quantum dots from time-resolved optical measurements

Cited by 131 publications

References 25 publications

Size-dependent oscillator strength and quantum efficiency of CdSe quantum dots controlled via the local density of states

Size-dependent oscillator strength and quantum efficiency of CdSe quantum dots controlled via the local density of states

Decay dynamics of quantum dots influenced by the local density of optical states of two-dimensional photonic crystal membranes

Extraction of the β-factor for single quantum dots coupled to a photonic crystal waveguide

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