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Spontaneous emission

About: Spontaneous emission is a research topic. Over the lifetime, 12855 publications have been published within this topic receiving 323684 citations.


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Journal ArticleDOI
TL;DR: The directional spontaneous emission of photons by laser-trapped caesium atoms into an optical nanofibre is demonstrated and the spontaneous emission into the counter-propagating guided modes from symmetric to strongly asymmetric, where more than % of the optical power is launched into one or the other direction.
Abstract: Nanoscale confinement in an optical fibre induces coupling between a photon’s spin and orbital angular momentum. Here, the authors use this effect to control the direction of photons spontaneously emitted from trapped caesium atoms into a nanofibre.

374 citations

Journal ArticleDOI
TL;DR: In this article, the authors classified and reviewed the physical mechanisms causing the efficiency droop in InGaN/GaN blue light-emitting diodes and remedies proposed for droop mitigation.
Abstract: Physical mechanisms causing the efficiency droop in InGaN/GaN blue light-emitting diodes and remedies proposed for droop mitigation are classified and reviewed. Droop mechanisms taken into consideration are Auger recombination, reduced active volume effects, carrier delocalization, and carrier leakage. The latter can in turn be promoted by polarization charges, inefficient hole injection, asymmetry between electron and hole densities and transport properties, lateral current crowding, quantum-well overfly by ballistic electrons, defect-related tunneling, and saturation of radiative recombination. Reviewed droop remedies include increasing the thickness or number of the quantum wells, improving the lateral current uniformity, engineering the quantum barriers (including multi-layer and graded quantum barriers), using insertion or injection layers, engineering the electron-blocking layer (EBL) (including InAlN, graded, polarization-doped, and superlattice EBL), exploiting reversed polarization (by either inverted epitaxy or N-polar growth), and growing along semi- or non-polar orientations. Numerical device simulations of a reference device are used through the paper as a proof of concept for selected mechanisms and remedies.

371 citations

Journal ArticleDOI
TL;DR: It is shown by atomistic simulations that a consistent part of the green gap in c-plane InGaN/GaN-based light emitting diodes may be attributed to a decrease in the radiative recombination coefficient with increasing indium content due to random fluctuations of the indium concentration naturally present in any In GaN alloy.
Abstract: White light emitting diodes (LEDs) based on III-nitride InGaN/GaN quantum wells currently offer the highest overall efficiency for solid state lighting applications. Although current phosphor-converted white LEDs have high electricity-to-light conversion efficiencies, it has been recently pointed out that the full potential of solid state lighting could be exploited only by color mixing approaches without employing phosphor-based wavelength conversion. Such an approach requires direct emitting LEDs of different colors, including, in particular, the green-yellow range of the visible spectrum. This range, however, suffers from a systematic drop in efficiency, known as the "green gap," whose physical origin has not been understood completely so far. In this work, we show by atomistic simulations that a consistent part of the green gap in c-plane InGaN/GaN-based light emitting diodes may be attributed to a decrease in the radiative recombination coefficient with increasing indium content due to random fluctuations of the indium concentration naturally present in any InGaN alloy.

364 citations

Journal ArticleDOI
TL;DR: In this paper, the rate equations for a microcavity semiconductor laser are solved and the steady-state behavior of the laser and some of its dynamic characteristics are investigated, and it is shown that by manipulating the mode density and the spontaneous decay rates of the cavity modes, the threshold gain can be decreased and the modulation speed can be improved.
Abstract: The rate equations for a microcavity semiconductor laser are solved and the steady-state behavior of the laser and some of its dynamic characteristics are investigated. It is shown that by manipulating the mode density and the spontaneous decay rates of the cavity modes, the threshold gain can be decreased and the modulation speed can be improved. However, in order to fully exploit the possibilities which the modification of the spontaneous decay opens up, the active material volume in the cavity must be smaller than a certain value. Threshold current using different definitions, population inversion factor, L-I curves, linewidth, and modulation response are discussed. >

363 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used the method of adiabatic following to prepare a single molecule in its fluorescing excited state, and showed that up to 74% of the sweeps lead to the emission of a single photon.
Abstract: We use the method of adiabatic following to prepare a single molecule in its fluorescing excited state. Spontaneous emission from this state gives rise to a single photon. With our current experimental conditions, up to 74% of the sweeps lead to the emission of a single photon. Since the adiabatic passage is done on command, the molecule performs as a high rate source of triggered photons. The experimental results are in quantitative agreement with quantum Monte Carlo simulations.

361 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202383
2022213
2021360
2020338
2019419
2018453