Generation and delayed retrieval of spatially multimode Raman scattering in warm rubidium vapors

Chrapkiewicz, Radosław; Wasilewski, Wojciech

doi:10.1364/oe.20.029540

Cited by 30 publications

(41 citation statements)

References 34 publications

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“…The entanglement distribution rate in these schemes scales linearly with the number of modes used for multiplexing. However, this requires quantum memories that can store large number of modes, which could be encoded in time [10,11], frequency [12], or space [13]. All quantum memory schemes based on atomic ensembles can be used for efficient spatial multimode storage [14].…”

Section: Introductionmentioning

confidence: 99%

Towards highly multimode optical quantum memory for quantum repeaters

et al. 2016

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Long-distance quantum communication through optical fibers is currently limited to a few hundreds of kilometres due to fiber losses. Quantum repeaters could extend this limit to continental distances. Most approaches to quantum repeaters require highly multimode quantum memories in order to reach high communication rates. The atomic frequency comb memory scheme can in principle achieve high temporal multimode storage, without sacrificing memory efficiency. However, previous demonstrations have been hampered by the difficulty of creating high-resolution atomic combs, which reduces the efficiency for multimode storage. In this article we present a comb preparation method that allows one to increase the multimode capacity for a fixed memory bandwidth. We apply the method to a 151 Eu 3+ -doped Y 2 SiO 5 crystal, in which we demonstrate storage of 100 modes for 51 μs using the AFC echo scheme (a delay-line memory) and storage of 50 modes for 0.541 ms using the AFC spin-wave memory (an on-demand memory). We also briefly discuss the ultimate multimode limit imposed by the optical decoherence rate, for a fixed memory bandwidth.

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Section: Introductionmentioning

confidence: 99%

Towards highly multimode optical quantum memory for quantum repeaters

et al. 2016

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“…We show that the intensity cross-correlation g 2 S;aS 0, which describes the simultaneous detection of Stokes and anti-Stokes photons, increases steadily with decreasing laser power and saturates at very low pump powers, implying that the number of Stokes-induced aS photons is comparable to the number of spontaneously generated aS photons. Furthermore, the coincidence rate shows a quadratic plus cubic power dependence, indicating the generation of multiple S photons per pulse at high powers.Raman scattering, typically used to probe the vibrational modes of a system, can also create correlated Stokesanti-Stokes photon pairs in bulk solids such as diamond [1][2][3] or in gases such as Cesium [4,5] or Rubidium vapor [6][7][8]. In the uncorrelated regime, both Stokes (S) and anti-Stokes (aS) intensities are linear with excitation laser power, i.e., a single laser photon spontaneously scatters into a single S or aS photon [see Fig.…”

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confidence: 99%

“…Raman scattering, typically used to probe the vibrational modes of a system, can also create correlated Stokesanti-Stokes photon pairs in bulk solids such as diamond [1][2][3] or in gases such as Cesium [4,5] or Rubidium vapor [6][7][8]. In the uncorrelated regime, both Stokes (S) and anti-Stokes (aS) intensities are linear with excitation laser power, i.e., a single laser photon spontaneously scatters into a single S or aS photon [see Fig.…”

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confidence: 99%

“…In this case, we expect that the aS intensity depends on the squared excitation laser power, since one laser photon creates the phonon in the S process, and another laser photon scatters from the phonon in the aS process [9,10]. Recent work has shown theoretically and experimentally that the Stokes-generated phonon (or spin wave, for Cesium [4,5] and Rubidium vapors [6][7][8]) acts as a quantum memory, where the S and aS signals act as write and read commands [1][2][3]9]. In parallel, research in photon pairs produced through four-wave mixing (FWM) in optical fibers has shown highly nonclassical correlations [11,12], analogous to studies in spontaneous parametric down-conversion (SPDC) [13,14].…”

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confidence: 99%

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Stokes–anti-Stokes correlations in diamond

et al. 2015

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We investigate the arrival statistics of Stokes (S) and anti-Stokes (aS) Raman photons generated in diamond membranes. Strong quantum correlations between the S and aS signals are observed, which implies that the two processes share the same phonon, that is, the phonon excited by the S process is consumed in the aS process. We show that the intensity cross-correlation g (2)S,aS (0), which describes the simultaneous detection of Stokes and anti-Stokes photons, decreases steadily with laser power as 1/PL. Contrary to many other material systems, diamond exhibits a maximum g (2)S,aS (0) at very low pump powers, implying that the Stokes-induced aS photons outnumber the thermally generated aS photons. On the other hand, the coincidence rate shows a quadratic plus cubic power dependence, which indicates a departure from the Stokes-induced anti-Stokes process.Raman scattering, conventionally used as a method for probing the vibrational modes of a system, can be used to create correlated Stokes-anti-Stokes photon pairs [1][2][3][4][5][6][7][8][9][10][11]. In the uncorrelated regime, Raman scattering is spontaneous and, without laser heating, both Stokes and anti-Stokes intensities are linear with excitation laser power (see Fig. 1a). However, if the phonon energies are high enough that the thermal phonon occupation is low, the spontaneous aS process is rare and correlations between Stokes and anti-Stokes photon generation set in (see in Fig. 1b). In this regime the aS intensity depends on the squared excitation laser power, since one laser photon writes the phonon, and another laser photon reads it. Recent work has shown both theoretically and experimentally that the Stokes-generated phonon acts as a quantum memory, where the Stokes and anti-Stokes signals act as write and read commands [1][2][3][4][5][6][7][8][9][10][11]. In parallel, research in photon pairs produced through four-wave mixing (FWM) in optical fibers has shown extremely high nonclassical correlations [12, 13], analogous to studies in spontaneous parametric downconversion (SPDC) [14].In this paper, we report the generation of highly nonclassical photon superbunching in diamond at low excitation powers and analyze Stokes-anti-Stokes photon correlations as a function of pump power. Our data reveal the range of conditions under which Stokes-induced anti-Stokes scattering (SaS) can be used to generate correlated photons in diamond. This information is useful for designing efficient phonon-based quantum memories and heralded single-photon sources for quantum communication. Contrary to four-wave mixing measurements in optical fibers [12] and spontaneous parametric down conversion in nonlinear crystals [14], we observe a saturation of Stokes-anti-Stokes correlations at very low intensities.In our experiments, we measure Stokes and anti-Stokes * Corresponding author: lnovotny@ethz.ch photons in diamond as a function of laser power P L . The excitation wavelength is λ = 785 nm and the Stokes and anti-Stokes photons appear at the wavelengths λ S = 880 nm and λ aS...

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“…Recently study of Raman scattering has been focused on atomic systems with metastable energy levels, such as alkaline atoms and some rare earth ions [6][7][8]. The long lifetime of these energy levels is ideal for storage of quantum information [9][10][11][12][13][14] and for quantum memory [15,16].…”

Section: Introductionmentioning

confidence: 99%

Mirrorless parametric oscillation in an atomic Raman process

et al. 2014

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We investigate experimentally and theoretically the onset of parametric oscillation in a single-pass atomic Raman scattering process without the optical feedback. We find that this Raman oscillation effect is due to the coherent buildup of the atomic spin waves, and therefore the threshold of the Raman pump power for the onset of the oscillation depends on the decoherence time of the atomic spin waves and the Raman coupling constant but is not sensitive to the loss of the Stokes field, unlike the effect of amplified spontaneous emission. A simple theory of atomic Raman process fits the experimental results very well. The long decoherence time of the atomic spin waves in the atomic Raman process leads to a threshold power as low as a few hundred microwatts.

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Generation and delayed retrieval of spatially multimode Raman scattering in warm rubidium vapors

Cited by 30 publications

References 34 publications

Towards highly multimode optical quantum memory for quantum repeaters

Towards highly multimode optical quantum memory for quantum repeaters

Stokes–anti-Stokes correlations in diamond

Mirrorless parametric oscillation in an atomic Raman process

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