Topic
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 paper, it was shown that thermal energy charge transfer is the primary source of excitation for high-lying Zn II and Cd II laser levels, with configurations of the type 3d 10nx and 4d 10 nx, respectively, whereas the main source of energy excitation of the Zn 2 and Zn 3d 94s 2 and 4D 95s 2 laser levels is Penning ionization.
Abstract: Experimental evidence from pulsed afterglow studies is presented which demonstrates that thermal energy charge transfer is the primary source of excitation for the high‐lying Zn II and Cd II laser levels, with configurations of the type 3d 10nx and 4d 10nx, respectively, whereas the main source of excitation of the Zn II and Cd II laser levels, with configurations of the type 3d 94s 2 and 4d 95s 2, is Penning ionization. The total velocity‐averaged cross sections for thermal energy charge exchange and for Penning ionization are measured to be of order 10−15 cm2. These large cross sections account for the relatively high efficiency and low threshold currents characteristic of He–Zn and He–Cd ion lasers. The intensity of spontaneous emission from laser levels excited in a flowing afterglow by charge‐transfer reactions is broken down into the component contributions: direct charge‐transfer excitation, radiative cascade, and collisional cascade excitation. The results are used to estimate the values of the in...
74 citations
TL;DR: The first theoretical model of Fourier domain mode locking operation in a moving spectral reference frame is presented, enabling efficient numerical treatment, despite the broad laser spectrum and the extremely long cavity.
Abstract: The first theoretical model of Fourier domain mode locking operation is presented. A specially tailored dynamic equation in a moving spectral reference frame is derived, enabling efficient numerical treatment, despite the broad laser spectrum and the extremely long cavity. The excellent agreement of the presented theory with experiment over a wide range of operation parameters enables a quantitative assessment of the relevant physical effects, such as the spectral loss modulation and gain saturation dynamics, amplified spontaneous emission, linewidth enhancement, and self-phase modulation.
74 citations
TL;DR: In this paper, the connection between quantum interference effects in optical beams and radiation fields emitted from atomic systems is discussed, and the role of correlations between the emitting systems and present examples of practical methods to implement two systems with non-orthogonal dipole moments.
Abstract: We discuss the connection between quantum interference effects in optical beams and radiation fields emitted from atomic systems. We illustrate this connection by a study of the first- and second-order correlation functions of optical fields and atomic dipole moments. We explore the role of correlations between the emitting systems and present examples of practical methods to implement two systems with non-orthogonal dipole moments. We also derive general conditions for quantum interference in a two-atom system and for a control of spontaneous emission. The relation between population trapping and dark states is also discussed. Moreover, we present quantum dressed-atom models of cancellation of spontaneous emission, amplification on dark transitions, fluorescence quenching and coherent population trapping.
74 citations
TL;DR: In this article, a single quantum dot was used in a micropost microcavity to generate triggered single photons, which led to a large enhancement of spontaneous emission rate and allowed for strong coupling and single-dot lasing.
Abstract: We have used a single quantum dot in a micropost microcavity to generate triggered single photons. Coupling between the quantum-dot dipole and the confined microcavity mode leads to a large enhancement of the spontaneous emission rate. This, in turn, leads to efficient coupling of the emitted photons into a single traveling-wave mode. Optimization of the microcavity design should lead to nearly unity efficiency, and could also allow for strong coupling and for single-dot lasing.
74 citations
TL;DR: In this article, the authors investigated the effect of the air hole depth and the cladding refractive index on the light extraction efficiency of various two-dimensional photonic crystal slab structures.
Abstract: Efficient light extraction from various two-dimensional photonic crystal slab structures is studied. By using the finite-difference time-domain method, effects of finite air-hole depth, and the cladding refractive index on the light extraction efficiency are investigated. The largest extraction efficiency is obtained in the photonic crystal slab with entirely drilled air hole patterns and large index contrast with the bottom cladding. Using InGaAsP quantum wells emitting at 1.5 /spl mu/m large enhancement of photoluminescence is observed from the slab structures with air-hole patterns fully transferred through the active medium and the bottom cladding. The photoluminescence enhancement relative to the as-grown wafer is /spl sim/8 in the oxide-supported slab and /spl sim/13 in the free-standing slab. The large light extraction enhancement results from the coupling to leaky modes above the light line of a band structure. In addition, the extraction behaviors of a triangular lattice and a square lattice are compared, and it is shown that their distinctive extraction characteristics well reflect the features of each band structure.
74 citations