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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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TL;DR: In this article, the authors present a statistical analysis of time-resolved spontaneous emission decay curves from ensembles of emitters, such as semiconductor quantum dots, with the aim of interpreting ubiquitous non-single-exponential decay.
Abstract: We present a statistical analysis of time-resolved spontaneous emission decay curves from ensembles of emitters, such as semiconductor quantum dots, with the aim of interpreting ubiquitous non-single-exponential decay. Contrary to what is widely assumed, the density of excited emitters and the intensity in an emission decay curve are not proportional, but the density is a time integral of the intensity. The integral relation is crucial to correctly interpret non-single-exponential decay. We derive the proper normalization for both a discrete and a continuous distribution of rates, where every decay component is multiplied by its radiative decay rate. A central result of our paper is the derivation of the emission decay curve when both radiative and nonradiative decays are independently distributed. In this case, the well-known emission quantum efficiency can no longer be expressed by a single number, but is also distributed. We derive a practical description of non-single-exponential emission decay curves in terms of a single distribution of decay rates; the resulting distribution is identified as the distribution of total decay rates weighted with the radiative rates. We apply our analysis to recent examples of colloidal quantum dot emission in suspensions and in photonic crystals, and we find that this important class of emitters is well described by a log-normal distribution of decay rates with a narrow and a broad distribution, respectively. Finally, we briefly discuss the Kohlrausch stretched-exponential model, and find that its normalization is ill defined for emitters with a realistic quantum efficiency of less than 100%.
189 citations
TL;DR: In this article, the state-of-the-art in the knowledge of rate coefficients, cross-sections, transition probabilities, and ionization equilibrium calculations is reviewed, and a short discussion of X-ray plasma sources and instrumental problems is presented.
Abstract: Soft X-ray spectroscopic diagnostics of laboratory plasmas are considered. To start with, the state of the art in the knowledge of rate coefficients, cross-sections, transition probabilities, and ionization equilibrium calculations is reviewed. Next, the plasma spectral emission, i.e. continuum and line emission (including satellites), line broadening (including opacity), and total emitted radiation as an energy loss process, is considered. To conclude, a short discussion of X-ray plasma sources and instrumental problems is presented.
188 citations
TL;DR: In this article, it was shown that spontaneous emission of an atom placed in a dielectric is proportional to the local radiative density of states, which is only a part of the local density of the eigenmodes of the Maxwell equations.
Abstract: We show rigorously that the coefficient for spontaneous emission of an atom placed in a dielectric is proportional to the local radiative density of states—that is only a part of the local density of the eigenmodes of the Maxwell equations. Spontaneous emission is inhibited if the atom is located at a position where this local radiative density is small, even if the total density of states is not vanishing. This radiative density of states can be obtained without having to perform a full quantum calculation of the radiation-matter system. We demonstrate this principle by solving numerically a scalar model for a dielectric that consists of a lattice of resonating dipoles.
187 citations
TL;DR: In this paper, it was shown that when the coupling between light and matter becomes strong enough, the Purcell effect decouples and the spontaneous emission rate decays with large enough couplings.
Abstract: Improvements in both the photonic confinement and the emitter design have led to a steady increase in the strength of the light-matter coupling in cavity quantum electrodynamics experiments. This has allowed us to access interaction-dominated regimes in which the state of the system can only be described in terms of mixed light-matter excitations. Here we show that, when the coupling between light and matter becomes strong enough, this picture breaks down, and light and matter degrees of freedom totally decouple. A striking consequence of such a counterintuitive phenomenon is that the Purcell effect is reversed and the spontaneous emission rate, usually thought to increase with the light-matter coupling strength, plummets instead for large enough couplings.
187 citations
TL;DR: In this article, the photoluminescence intensity increases in the cavity axis direction, and the spontaneous emission lifetime is experimentally found to decrease with an on-resonance cavity structure.
Abstract: Enhanced spontaneous emission has been observed with wavelength‐sized monolithic Fabry–Perot cavities containing GaAs quantum wells. With an on‐resonance cavity structure, the photoluminescence intensity increases in the cavity axis direction, and the spontaneous emission lifetime is experimentally found to decrease.
184 citations