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Atomic coherence
About: Atomic coherence is a research topic. Over the lifetime, 877 publications have been published within this topic receiving 29395 citations.
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TL;DR: In this paper, it is shown that a specific sub-radiant state is naturally developed in the absorber due to the formation of the spatial domains of the atomic coherence with opposite phases.
Abstract: The propagation of a step pulse through a thick resonant absorber with a homogeneously broadened absorption line is considered. It is shown that a specific subradiant state is naturally developed in the absorber due to the formation of the spatial domains of the atomic coherence with opposite phases. It is proposed to divide the absorber into slices in accordance with these domains and place the phase shifters in front of the first slice and between the other slices. If the phase shifters are switched on simultaneously at a particular moment of time, elapsed from the beginning of the step pulse, a strong sharp pulse is generated at the output of the last slice of the absorber. The effect is explained by the phasing of the atomic coherence along all slices of the absorber, which transforms the subradiant state of the atom-field system to a superradiant state.
2 citations
TL;DR: In this article, the authors studied the squeezing spectrum of the fluorescence field emitted from a four-level atom in a configuration driven by two coherent fields and found that the squeezing properties were significantly influenced by the presence of vacuum-induced coherence in the atomic system.
Abstract: The squeezing spectrum of the fluorescence field emitted from a four-level atom in $J=1/2$ to $J=1/2$ configuration driven by two coherent fields is studied. We find that the squeezing properties of the fluorescence radiation are significantly influenced by the presence of vacuum-induced coherence in the atomic system. It is shown that such coherence induces spectral squeezing in phase quadratures of the fluorescence light for both weak and strong driving fields. The dependence of the squeezing spectrum on the relative phase of the driving fields is also investigated. Effects such as enhancement or suppression of the squeezing peaks are shown in the spectrum as the relative phase is varied. An analytical explanation of the numerical findings is presented using dressed-states of the atom-field system.
2 citations
TL;DR: In this paper, the effect of strong laser pulses on the evolution of an atomic or molecular wave function is analyzed in the context of coherent control in the strong-field regime, when power broadening and dynamic Stark shifts become comparable with or bigger than the bandwidth of the control field.
Abstract: Understanding the effect of strong laser pulses on the evolution of an atomic or molecular wave function is important in the context of coherent control in the strong-field regime, when power broadening and dynamic Stark shifts become comparable with or bigger than the bandwidth of the control field. We experimentally demonstrate the method of complete characterization of a complex-valued amplitude of a quantum state driven by a strong two-photon field. The method is based on coherent scattering of a weak probe pulse from the strong-field-induced atomic coherence, followed by the detection of the time- and frequency-resolved parametric four-wave-mixing signal. We show that the proposed technique corresponds to a cross-correlation frequency-resolved optical gating (XFROG) of the highly perturbed evolution of an atomic quantum state. Utilizing the XFROG retrieval algorithm, we determine both the amplitude and phase of an atomic wave function at any time moment throughout the interaction with the driving field. The direct retrieval of the time-dependent phase of the wave function, rather than the population dynamics only, enables us to observe the strong-field effects with arbitrary time and frequency resolution.
2 citations
23 May 1999
TL;DR: A tightly focused and rapidly rotating blue-detuned laser beam was used to trap rubidium atoms in the dark with long atomic coherence times as discussed by the authors, which yielded atomic densities well above 10/sup 13/ cm/sup -3/
Abstract: Summary form only given A tightly focused and rapidly rotating blue-detuned laser beam was used to trap rubidium atoms in the dark with long atomic coherence times Adiabatic compression and laser cooling then yielded atomic densities well above 10/sup 13/ cm/sup -3/
2 citations
TL;DR: It is shown that finite (large) atomic coherence can be generated by (incoherent) pumping of the intermediate states, which removes the destructive interference effects that otherwise inhibit coherent emission of signals.
Abstract: Enhanced emission of a coherent signal generated by the nonlinear process ωf+ωb-ωp has been found in an incoherently pumped four-level system. It is shown that finite (large) atomic coherence can be generated by (incoherent) pumping of the intermediate states, which removes the destructive interference effects that otherwise inhibit coherent emission of signals.
2 citations