Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:1109.5110 · Physical Review A

Quantum-state storage and processing for polarization qubits in an inhomogeneously broadened Λ -type three-level medium

Daniel Viscor, Alessandro Ferraro, Yu. V. Loiko, J. Mompart, V. Ahufinger

Published Oct 7, 2011• 7 citations
arXivHTMLPDF

Abstract

We address the propagation of a single-photon pulse with two polarization components, i.e., a polarization qubit, in an inhomogeneously broadened ``phaseonium'' $\ensuremath{\Lambda}$-type three-level medium. We combine some of the nontrivial propagation effects characteristic for this kind of coherently prepared systems and the controlled reversible inhomogeneous broadening technique to propose several quantum information-processing applications, such as a protocol for polarization qubit filtering and sieving as well as a tunable polarization beam splitter. Moreover, we show that by imposing a spatial variation of the atomic coherence phase, an efficient quantum memory for the incident polarization qubit can be also implemented in $\ensuremath{\Lambda}$-type three-level systems.

DOI
10.1103/physreva.84.042314

Related papers

Optical quantum memory for polarization qubits withV-type three-level atoms

Daniel Viscor, Alessandro Ferraro, Yu. V. Loiko +3 more

We investigate an optical quantum memory scheme with V-type three-level atoms based on the controlled reversible inhomogeneous broadening (CRIB) technique. We theoretically show the possibility to store and retrieve a weak light pulse interacting with the two optical transitions of the system. This scheme implements a quantum memory for a polarization qubit - a single photon in an arbitrary polarization state - without the need of two spatially separated two-level media, thus offering the advantage of experimental compactness overcoming the limitations due to mismatching and unequal efficiencies that can arise in spatially separated memories. The effects of a relative phase change between the atomic levels, as well as of phase noise due to, for example, the presence of spurious electric and magnetic fields are analyzed.

arXiv:1112.6112•Journal of Physics B Atomic Molecular and Optical Physics•Sep 13, 2011•7 citations

An efficient quantum memory based on two-level atoms

Ivan Iakoupov, Anders Søndberg Sørensen

We propose a method to implement a quantum memory for light based on ensembles of two-level atoms. Our protocol is based on controlled reversible inhomogeneous broadening (CRIB), where an external field first dephases the atomic polarization and thereby stores an incoming light pulse into collective states of the atomic ensemble, and later a reversal of the applied field leads to a rephasing of the atomic polarization and a reemission of the light. As opposed to previous proposals for CRIB-based quantum memories, we propose only applying the broadening for a short period after most of the pulse has already been absorbed by the ensemble. We show that with this procedure there exist certain modes of the incoming light field that can be stored with an efficiency approaching 100% in the limit of high optical depth and long coherence time of the atoms. These results demonstrate that it is possible to operate an efficient quantum memory without any optical control fields.

arXiv:1301.0705•New Journal of Physics•Aug 13, 2013•17 citations

High-efficiency quantum memory for photonic polarization qubits in a spatially-multiplexed dense cold atomic ensemble

Kun Huang, Pierre Vernaz-Gris, Mingtao Cao +2 more

Quantum storage of flying optical qubits, namely coherently mapping photonic states into and out of an optically controlled memory on demand, constitutes an essential component in the optical quantum information processing science, with applications to long-distance optical communication [1]. In this context, practical protocols require sufficiently large storage efficiency to achieve a performance better than direct transmission. Theoretically, the storage and retrieval efficiency can only be improved with the increase of the optical depth (OD). Recent progresses have shown that high OD media enable to reach high-efficiency electromagnetically induced transparency (EIT)-based optical storage, albeit without the demonstration of qubit storage [2, 3]. Here we experimentally implement an optical quantum memory with single-photon-level probes, showing a EIT-based storage efficiency around 70%. Furthermore, thanks to the spatial multiplexing of the dense atomic ensemble, highly efficient storage of polarization qubit is performed.

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)•Jun 1, 2017•1 citation

Photon storage in Λ -type optically dense atomic media. III. Effects of inhomogeneous broadening

Alexey Vyacheslavovich Gorshkov, Axel André, Mikhail D. Lukin +1 more

In a recent paper [Gorshkov et al., Phys. Rev. Lett. 98, 123601 (2007)] and in the two preceding papers [Gorshkov et al., this issue, Phys. Rev. A 76, 033804 (2006); 76, 033805 (2006)], we used a universal physical picture to optimize and demonstrate equivalence between a wide range of techniques for storage and retrieval of photon wave packets in homogeneously broadened $\ensuremath{\Lambda}$-type atomic media, including the adiabatic reduction of the photon group velocity, pulse-propagation control via off-resonant Raman techniques, and photon-echo-based techniques. In the present paper, we generalize this treatment to include inhomogeneous broadening. In particular, we consider the case of Doppler-broadened atoms and assume that there is a negligible difference between the Doppler shifts of the two optical transitions. In this situation, we show that, at high enough optical depth, all atoms contribute coherently to the storage process as if the medium were homogeneously broadened. We also discuss the effects of inhomogeneous broadening in solid state samples. In this context, we discuss the advantages and limitations of reversing the inhomogeneous broadening during the storage time, as well as suggest a way for achieving high efficiencies with a nonreversible inhomogeneous profile.

arXiv:quant-ph/0612084•Physical Review A•Sep 7, 2007•76 citations

Highly-efficient quantum memory for polarization qubits in a spatially-multiplexed cold atomic ensemble

Pierre Vernaz-Gris, Kun Huang, Mingtao Cao +2 more

Quantum memory for flying optical qubits is a key enabler for a wide range of applications in quantum information. A critical figure of merit is the overall storage and retrieval efficiency. So far, despite the recent achievements of efficient memories for light pulses, the storage of qubits has suffered from limited efficiency. Here we report on a quantum memory for polarization qubits that combines an average conditional fidelity above 99% and efficiency around 68%, thereby demonstrating a reversible qubit mapping where more information is retrieved than lost. The qubits are encoded with weak coherent states at the single-photon level and the memory is based on electromagnetically-induced transparency in an elongated laser-cooled ensemble of cesium atoms, spatially multiplexed for dual-rail storage. This implementation preserves high optical depth on both rails, without compromise between multiplexing and storage efficiency. Our work provides an efficient node for future tests of quantum network functionalities and advanced photonic circuits.

arXiv:1707.09372•Nature Communications•Jan 19, 2018•181 citations

Controllably releasing long-lived quantum memory for photonic polarization qubit into multiple separate photonic channels

Lirong Chen, Zhongxiao Xu, Weiqing Zeng +3 more

We report an experiment in which long-lived quantum memories for photonic polarization qubits (PPQs) are controllably released into any one of multiple separate channels. The PPQs are implemented with an arbitrarily-polarized coherent signal light pulses at the single-photon level and are stored in cold atoms by means of electromagnetic-induced-transparency scheme. Reading laser pulses propagating along the direction at a small angle relative to quantum axis are applied to release the stored PPQs into an output channel. By changing the propagating directions of the read laser beam, we controllably release the retrieved PPQs into 7 different photonic output channels, respectively. At one of the output channels, the measured maximum quantum-process fidelity for the PPQs is 94.2% at storage time of t= 0.85ms. At storage time of 6 ms, the quantum-process fidelity is still beyond 78%, the threshold for the violation of the Bell inequality. The demonstrated controllable release of the stored PPQs may extend the capabilities of the quantum information storage technique.

arXiv:1606.02123•Jun 7, 2016•0 citations
We address the propagation of a single-photon pulse with two polarization components, i.e., a polarization qubit, in an inhomogeneously broadened ``phaseonium'' \ensuremathΛ\ensuremath{\Lambda}\ensuremathΛ-type three-level medium. We combine some of the nontrivial propagation effects characteristic for this kind of coherently prepared systems and the controlled reversible inhomogeneous broadening technique to propose several quantum information-processing applications, such as a protocol for polarization qubit filtering and sieving as well as a tunable polarization beam splitter. Moreover, we show that by imposing a spatial variation of the atomic coherence phase, an efficient quantum memory for the incident polarization qubit can be also implemented in \ensuremathΛ\ensuremath{\Lambda}\ensuremathΛ-type three-level systems.
We investigate an optical quantum memory scheme with V-type three-level atoms based on the controlled reversible inhomogeneous broadening (CRIB) technique. We theoretically show the possibility to store and retrieve a weak light pulse interacting with the two optical transitions of the system. This scheme implements a quantum memory for a polarization qubit - a single photon in an arbitrary polarization state - without the need of two spatially separated two-level media, thus offering the advantage of experimental compactness overcoming the limitations due to mismatching and unequal efficiencies that can arise in spatially separated memories. The effects of a relative phase change between the atomic levels, as well as of phase noise due to, for example, the presence of spurious electric and magnetic fields are analyzed.
We propose a method to implement a quantum memory for light based on ensembles of two-level atoms. Our protocol is based on controlled reversible inhomogeneous broadening (CRIB), where an external field first dephases the atomic polarization and thereby stores an incoming light pulse into collective states of the atomic ensemble, and later a reversal of the applied field leads to a rephasing of the atomic polarization and a reemission of the light. As opposed to previous proposals for CRIB-based quantum memories, we propose only applying the broadening for a short period after most of the pulse has already been absorbed by the ensemble. We show that with this procedure there exist certain modes of the incoming light field that can be stored with an efficiency approaching 100% in the limit of high optical depth and long coherence time of the atoms. These results demonstrate that it is possible to operate an efficient quantum memory without any optical control fields.
Quantum storage of flying optical qubits, namely coherently mapping photonic states into and out of an optically controlled memory on demand, constitutes an essential component in the optical quantum information processing science, with applications to long-distance optical communication [1]. In this context, practical protocols require sufficiently large storage efficiency to achieve a performance better than direct transmission. Theoretically, the storage and retrieval efficiency can only be improved with the increase of the optical depth (OD). Recent progresses have shown that high OD media enable to reach high-efficiency electromagnetically induced transparency (EIT)-based optical storage, albeit without the demonstration of qubit storage [2, 3]. Here we experimentally implement an optical quantum memory with single-photon-level probes, showing a EIT-based storage efficiency around 70%. Furthermore, thanks to the spatial multiplexing of the dense atomic ensemble, highly efficient storage of polarization qubit is performed.
In a recent paper [Gorshkov et al., Phys. Rev. Lett. 98, 123601 (2007)] and in the two preceding papers [Gorshkov et al., this issue, Phys. Rev. A 76, 033804 (2006); 76, 033805 (2006)], we used a universal physical picture to optimize and demonstrate equivalence between a wide range of techniques for storage and retrieval of photon wave packets in homogeneously broadened $\ensuremath{\Lambda}$-type atomic media, including the adiabatic reduction of the photon group velocity, pulse-propagation control via off-resonant Raman techniques, and photon-echo-based techniques. In the present paper, we generalize this treatment to include inhomogeneous broadening. In particular, we consider the case of Doppler-broadened atoms and assume that there is a negligible difference between the Doppler shifts of the two optical transitions. In this situation, we show that, at high enough optical depth, all atoms contribute coherently to the storage process as if the medium were homogeneously broadened. We also discuss the effects of inhomogeneous broadening in solid state samples. In this context, we discuss the advantages and limitations of reversing the inhomogeneous broadening during the storage time, as well as suggest a way for achieving high efficiencies with a nonreversible inhomogeneous profile.
Quantum memory for flying optical qubits is a key enabler for a wide range of applications in quantum information. A critical figure of merit is the overall storage and retrieval efficiency. So far, despite the recent achievements of efficient memories for light pulses, the storage of qubits has suffered from limited efficiency. Here we report on a quantum memory for polarization qubits that combines an average conditional fidelity above 99% and efficiency around 68%, thereby demonstrating a reversible qubit mapping where more information is retrieved than lost. The qubits are encoded with weak coherent states at the single-photon level and the memory is based on electromagnetically-induced transparency in an elongated laser-cooled ensemble of cesium atoms, spatially multiplexed for dual-rail storage. This implementation preserves high optical depth on both rails, without compromise between multiplexing and storage efficiency. Our work provides an efficient node for future tests of quantum network functionalities and advanced photonic circuits.
We report an experiment in which long-lived quantum memories for photonic polarization qubits (PPQs) are controllably released into any one of multiple separate channels. The PPQs are implemented with an arbitrarily-polarized coherent signal light pulses at the single-photon level and are stored in cold atoms by means of electromagnetic-induced-transparency scheme. Reading laser pulses propagating along the direction at a small angle relative to quantum axis are applied to release the stored PPQs into an output channel. By changing the propagating directions of the read laser beam, we controllably release the retrieved PPQs into 7 different photonic output channels, respectively. At one of the output channels, the measured maximum quantum-process fidelity for the PPQs is 94.2% at storage time of t= 0.85ms. At storage time of 6 ms, the quantum-process fidelity is still beyond 78%, the threshold for the violation of the Bell inequality. The demonstrated controllable release of the stored PPQs may extend the capabilities of the quantum information storage technique.