On the polarized emission from exciton complexes in GaN quantum dots

Amloy, Supaluck; Karlsson, K. F.; Andersson, T. G.; Holtz, Per-Olof

doi:10.1063/1.3675572

Cited by 21 publications

(23 citation statements)

References 16 publications

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“…It was earlier argued that the exciton and biexciton emission lines from the same QD do exhibit almost identical polarization properties [14]. We have here monitored a polarization dependence (inserts of figure 2a) which is in consistence with the nearly identical polarization behavior for the exciton and biexciton.…”

Section: Resultssupporting

confidence: 74%

Polarized single photon emission and photon bunching from an InGaN quantum dot on a GaN micropyramid

Jemsson

Machhadani²,

Holtz³

et al. 2015

Nanotechnology

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We report on excitonic single photon emission and biexcitonic photon bunching from an InGaN quantum dot formed on the apex of a hexagonal GaN micropyramid. An approach to suppress uncorrelated emission from the pyramid base is proposed, a metal film is demonstrated to effectively screen background emission and thereby significantly enhance the signal-to-background ratio of the quantum dot emission. As a result, the second order coherence function at zero time delay g (2) (0) is significantly reduced (to g (2) (0) = 0.24, raw value) for the excitonic autocorrelation at a temperature of 12 K under continuous wave excitation, and a dominating single photon emission is demonstrated to survive up to 50 K. The deterioration of the g (2) (0)-value at elevated temperatures is well understood as the combined effect of reduced signal-to-background ratio and limited time resolution of the setup. This result underlines the great potential of site controlled pyramidal dots as sources of fast polarized single photons.

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Section: Resultssupporting

confidence: 74%

Polarized single photon emission and photon bunching from an InGaN quantum dot on a GaN micropyramid

Jemsson

Machhadani²,

Holtz³

et al. 2015

Nanotechnology

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“…2A shows the electric field distribution inside the silver-coated pyramid structure, which has a dipole source polarized along the y axis near the apex of the pyramid (see Fig. 5B) (29,30). As clearly shown in the magnetic field profiles (Fig.…”

Section: Resultsmentioning

confidence: 99%

Self-aligned deterministic coupling of single quantum emitter to nanofocused plasmonic modes

Gong

Kim

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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The quantum plasmonics field has emerged and been growing increasingly, including study of single emitter-light coupling using plasmonic system and scalable quantum plasmonic circuit. This offers opportunity for the quantum control of light with compact device footprint. However, coupling of a single emitter to highly localized plasmonic mode with nanoscale precision remains an important challenge. Today, the spatial overlap between metallic structure and single emitter mostly relies either on chance or on advanced nanopositioning control. Here, we demonstrate deterministic coupling between three-dimensionally nanofocused plasmonic modes and single quantum dots (QDs) without any positioning for single QDs. By depositing a thin silver layer on a site-controlled pyramid QD wafer, three-dimensional plasmonic nanofocusing on each QD at the pyramid apex is geometrically achieved through the silver-coated pyramid facets. Enhancement of the QD spontaneous emission rate as high as 22 ± 16 is measured for all processed QDs emitting over ∼150-meV spectral range. This approach could apply to high fabrication yield onchip devices for wide application fields, e.g., high-efficiency light-emitting devices and quantum information processing.exciton-photon coupling | plasmonic nanofocusing | deterministic coupling | single-quantum emitter | Purcell effect S olid-state quantum photon sources based on semiconductor quantum dots (QDs) are a promising platform to realize scalable quantum technology (1-7). However, owing to the extremely small size of QDs (a few tens of nanometers) compared with the wavelength of light (a few hundreds of nanometers), the QD interaction with the photon field is very poor. This poor interaction results in rather low intrinsic spontaneous emission (SE) rates (8, 9), limiting the optical properties of single QDs: low repetition rate, higher sensitivity to thermally activated nonradiative processes and to dephasing from solid-state environment, etc. To overcome these limitations, there have been extensive efforts during the past decade to achieve deterministic coupling of a QD to intense photonic modes for strong Purcell effect (10-13), which demands spectral and spatial overlap between them. Due to the uncertainty of the size and position of the QD, it is still quite challenging and requires sophisticated control techniques, such as scanning probe microscopy and nanoscale positioning system (12,14,15). Therefore, demonstration of deterministic coupling is limited to few devices because the process has to be customized for each QD on the wafer.Nanofocusing of surface plasmon polaritons, beyond the light diffraction limit, has recently seen rapid development. This nanofocusing can be achieved using various tapered metallic structures, such as a sharp metal edge, V-shaped wedges, and tapered waveguides (16-21). Tapering a metallic structure in all three dimensions, instead of only two, is considered ideal for ultimate light focusing (20, 21). The resulting extremely small mode volume can permit strong coupl...

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“…22 Numerical computations predict a high degree of polarization for small or moderate in-plane shape anisotropy of GaN and InGaN QDs. 32,33 This is related to the intrinsic valence band structure of the III-Ns. To reach P>0.95, an in-plane shape elongation of 1.25 : 1 is needed for an InGaN QD, 23,33 while a corresponding aspect ratio of 2.5 : 1 is needed for GaN QDs.…”

Section: Qd Emission With Controllable Polarization Direction a Lundsmentioning

confidence: 99%

“…To reach P>0.95, an in-plane shape elongation of 1.25 : 1 is needed for an InGaN QD, 23,33 while a corresponding aspect ratio of 2.5 : 1 is needed for GaN QDs. 32 In particular, we have identified the split-off energy as the key material parameter determining the degree of polarization for a given asymmetry.…”

Section: Qd Emission With Controllable Polarization Direction a Lundsmentioning

confidence: 99%

Direct generation of linearly polarized photon emission with designated orientations from site-controlled InGaN quantum dots

et al. 2014

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Semiconductor quantum dots (QDs) have been demonstrated viable for efficient light emission applications, in particular for the emission of single photons on demand. However, the preparation of QDs emitting photons with predefined and deterministic polarization vectors has proven arduous. Access to linearly polarized photons is essential for various applications. In this report, a novel concept to directly generate linearly-polarized photons is presented. This concept is based on InGaN QDs grown on top of elongated GaN hexagonal pyramids, by which the predefined elongation determines the polarization vectors of the emitted photons from the QDs. This growth scheme should allow fabrication of ultracompact arrays of photon emitters, with a controlled polarization direction for each individual emitter. Keywords: GaN; InGaN; photoluminescence; polarized emission; quantum dot INTRODUCTION Quantum dots (QDs) have validated their important role in current optoelectronic devices and they are also seen promising as light sources for quantum information applications. An improved efficiency of laser diodes and light-emitting diodes can be achieved by the incorporation of QDs ensembles in the optically active layers.1 In addition, the proposed quantum computer applications rely on photons with distinct energy and polarization vectors, which can be seen as the ultimate demand on photons emitted from individual QDs.2 A common requirement raised for several optoelectronic applications, e.g., liquid-crystal displays, three-dimensional visualization, (bio)-dermatology 3 and the optical quantum computers, 4 is the need of linearly polarized light for their operation. For existing applications, the generation of linearly polarized light is obtained by passing unpolarized light through a combination of polarization selective filters and waveguides, with an inevitable efficiency loss as the result. These losses can be drastically reduced by employment of sources, which directly generate photons with desired polarization directions.Conventional QDs grown via the Stranski-Krastanov (SK) growth mode are typically randomly distributed over planar substrates and possess different degrees of anisotropies. The anisotropy in strain field and/or geometrical shape of each individual QD determines the polarization performance of the QD emission. Accordingly, a cumbersome post-selection of QDs with desired polarization properties among the randomly distributed QDs is required for device integration.

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On the polarized emission from exciton complexes in GaN quantum dots

Cited by 21 publications

References 16 publications

Polarized single photon emission and photon bunching from an InGaN quantum dot on a GaN micropyramid

Polarized single photon emission and photon bunching from an InGaN quantum dot on a GaN micropyramid

Self-aligned deterministic coupling of single quantum emitter to nanofocused plasmonic modes

Direct generation of linearly polarized photon emission with designated orientations from site-controlled InGaN quantum dots

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