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 article, the two-time Green function method in quantum electrodynamics of high-Z few-electron atoms is described in detail and a simple procedure for deriving formulas for the energy shift of a single level and for the energies and wave functions of degenerate and quasi-degenerate states is provided.
Abstract: The two-time Green function method in quantum electrodynamics of high-Z few-electron atoms is described in detail. This method provides a simple procedure for deriving formulas for the energy shift of a single level and for the energies and wave functions of degenerate and quasi-degenerate states. It also allows one to derive formulas for the transition and scattering amplitudes. Application of the method to resonance scattering processes yields a systematic theory for the spectral line shape. The practical ability of the method is demonstrated by deriving formulas for the QED and interelectronic-interaction corrections to energy levels and transition and scattering amplitudes in one-, two-, and three-electron atoms. Numerical calculations of the Lamb shift, the hyperfine splitting, the bound-electron g factor, and the radiative recombination cross section in heavy ions are also reviewed.
183 citations
TL;DR: In this paper, the authors present a circuit design that effectively eliminates spontaneous emission due to the Purcell effect while maintaining strong coupling to a low-Q cavity, using fast (nanosecond time-scale) flux biasing of the qubit, demonstrating in situ control of qubit lifetime over a factor of 50.
Abstract: Spontaneous emission through a coupled cavity can be a significant decay channel for qubits in circuit quantum electrodynamics. We present a circuit design that effectively eliminates spontaneous emission due to the Purcell effect while maintaining strong coupling to a low-Q cavity. Excellent agreement over a wide range in frequency is found between measured qubit relaxation times and the predictions of a circuit model. Using fast (nanosecond time-scale) flux biasing of the qubit, we demonstrate in situ control of qubit lifetime over a factor of 50. We realize qubit reset with 99.9% fidelity in 120 ns.
183 citations
TL;DR: It is shown that an excess spontaneous emission of this type, and also a correlation between the spontaneous emission into different cavity modes, will in fact be present in all open-sided laser resonators or optical lens guides.
Abstract: Petermann first predicted in 1979 the existence of an excess-spontaneous-emission factor in gain-guided semiconductor lasers. We show that an excess spontaneous emission of this type, and also a correlation between the spontaneous emission into different cavity modes, will in fact be present in all open-sided laser resonators or optical lens guides. These properties arise from the non-self-adjoint or non-power-orthogonal nature of the optical resonator modes. The spontaneous-emission rate is only slightly enhanced in stable-resonator or index-guided structures, but can become very much larger than normal in gain-guided or geometrically unstable structures. Optical resonators or lens guides that have an excess noise emission necessarily also exhibit an ``excess initial-mode excitation factor'' for externally injected signals. As a result, the excess spontaneous emission can be balanced out and the usual quantum-noise limit recovered in laser amplifiers and in injection-seeded laser oscillators, but not in free-running laser oscillators.
182 citations
TL;DR: It is demonstrated that this exceptional condition results in the effective cancellation of spontaneous emission, in the onset of stimulated emission at exceedingly low excitation levels, and in an anomalously high stimulated-emission gain.
Abstract: In an active ``microcavity'' the condition of maximum ``enhancement'' of spontaneous emission corresponds to resonant coupling of atoms with a single field mode. We demonstrate that this exceptional condition results in the effective cancellation of spontaneous emission, in the onset of stimulated emission at exceedingly low excitation levels, and in an anomalously high stimulated-emission gain. In the context of phase-transition theory the active microcavity behaves as a statistical ensemble undergoing an order-disorder transition at an extremely high value of the critical temperature.
182 citations
TL;DR: In this article, the spontaneous emission process of an optical, dipolar emitter in metal-dielectric-metal slab and slot waveguide structures was theoretically investigated, and it was shown that both structures exhibit strong emission enhancements at nonresonant conditions, due to the tight confinement of modes between two metallic plates.
Abstract: We theoretically investigate the spontaneous emission process of an optical, dipolar emitter in metal-dielectric-metal slab and slot waveguide structures. We find that both structures exhibit strong emission enhancements at nonresonant conditions, due to the tight confinement of modes between two metallic plates. The large enhancement of surface plasmon-polariton excitation enables dipole emission to be preferentially coupled into plasmon waveguide modes. These structures find applications in creating nanoscale local light sources or in generating guided single plasmons in integrated optical circuits.
182 citations