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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: Eisaman et al. as mentioned in this paper used a room-temperature ensemble of 87Rb atoms to generate a single photon using electromagnetically induced transparency (EIT).
Abstract: We review recent experiments [M. D. Eisaman et al., Nature438 (2005) 837] demonstrating the generation of narrow-bandwidth single photons using a room-temperature ensemble of 87Rb atoms. Our method involves creation of an atomic coherence via Raman scattering and projective measurement, followed by the coherent transfer of this atomic coherence onto a single photon using electromagnetically induced transparency (EIT). The single photons generated using this method are shown to have many properties necessary for quantum information protocols, such as narrow bandwidths, directional emission, and controllable pulse shapes. The narrow bandwidths of these single photons (~MHz), resulting from their matching to the EIT resonance (~MHz), allow them to be stored in narrow-bandwidth quantum memories. We demonstrate this by using dynamic EIT to store and retrieve the single photons in a second ensemble for storage times up to a few microseconds. We also describe recent improvements to the single-photon fidelity compared to the work by M. D. Eisaman in Nature438 (2005) 837. These techniques may prove useful in quantum information applications such as quantum repeaters, linear-optics quantum computation, and daytime free-space quantum communication.
16 citations
TL;DR: The present scheme is focused on the full-resonant interaction not only between the classical fields, the cavity modes and the bare atoms, but also between the Bogoliubov modes and dressed atoms, which will induce the one-way steering simply via adjusting the intensity of an external field.
Abstract: We explore the asymmetric Einstein-Podolsky-Rosen (EPR) steering of field modes via atomic coherent effects. A resonant four-level system in double-cascade configuration is under our consideration, where the atoms are excited by the applied fields from one cascade channel and two cavity modes are generated from the other cascade transition. The results show two cavity modes are suitable for achieving the steady-state one-way EPR steering. We analyze the physics in terms of the dressed-atom Bogoliubov-field-mode approach. It is found that one of two Bogoliubov modes is mediated by the resonant coupling of the dressed atoms and the other is decoupled from them. This leads to the so-called one-channel dissipation, by which the dressed atoms absorb the average excitations from one transformed mode and then two original modes are pulled into the asymmetric correlation. Remarkably, the present scheme is focused on the full-resonant interaction not only between the classical fields, the cavity modes and the bare atoms, but also between the Bogoliubov modes and dressed atoms, which will induce the one-way steering simply via adjusting the intensity of an external field. Furthermore, the EPR steering could occur between the field modes with the large frequency difference, such as optical and microwave fields, which is more useful for the practical quantum communication. Based on the one-channel dissipation, the obtainable one-way EPR steering is rather against the dynamic fluctuations and is regardless of the initial state.
16 citations
TL;DR: In this article, the authors demonstrate a dynamic hysteresis of the Raman scattered optical field in response to changes of the drive laser field intensity and/or frequency, which may be described as a dynamic form of optical bistability resulting from the formation and decay of atomic coherence.
Abstract: We report observations of novel dynamic behavior in resonantly enhanced stimulated Raman scattering in Rb vapor. In particular, we demonstrate a dynamic hysteresis of the Raman scattered optical field in response to changes of the drive laser field intensity and/or frequency. This effect may be described as a dynamic form of optical bistability resulting from the formation and decay of atomic coherence. We have applied this phenomenon to the realization of an all-optical switch.
16 citations
TL;DR: In this article, sub-Doppler absorption has been observed in Doppler-broadened cesium vapor cell via the Λ-type three-level scheme.
Abstract: Thanks to the atomic coherence in the coupling-laser-driven atomic system, sub-Doppler absorption has been observed in Doppler-broadened cesium vapor cell via the Λ-type three-level scheme. The linewidth of the sub-Doppler absorption peak becomes narrower while the frequency detuning of coupling laser increases. The results are in agreement with the theoretical prediction by G. Vemuri et al.
16 citations
TL;DR: In this paper, a different scheme to achieve temporal cloaking in warm atomic vapors was proposed, where instead of creating a temporal-spatial window in a patched broadband short optical pulse using static differential dispersion of an optical fiber, the propagation velocities of a pair of correlated narrow-band long optical pulses were directly controlled.
Abstract: We discuss a different scheme to achieve temporal cloaking in warm atomic vapors. Instead of creating a temporal-spatial window in a patched broadband short optical pulse using static differential dispersion of an optical fiber, we create a temporal-spatial window by directly controlling the propagation velocities of a pair of correlated narrow-band long optical pulses. This method eliminates the phase noise introduced by the broadband short-pulse swapping technique. When the eventmedium has a fast relaxation rate this leads to a temporal-cloaking scheme similar to that reported in fibers. When the event-medium relaxation cannot be neglected, we discuss a matched-mode scheme that can eliminate the phase change caused by the event field. The advantages of the dynamically and actively controlled atomic system over previously reported work are discussed. DOI: 10.1103/PhysRevA.87.023839
15 citations