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Broadband waveguide quantum memory for entangled photons


The reversible transfer of quantum states of light into and out of matter constitutes an important building block for future applications of quantum communication: it will allow the synchronization of quantum information1, and the construction of quantum repeaters2 and quantum networks3. Much effort has been devoted to the development of such quantum memories1, the key property of which is the preservation of entanglement during storage. Here we report the reversible transfer of photon–photon entanglement into entanglement between a photon and a collective atomic excitation in a solid-state device. Towards this end, we employ a thulium-doped lithium niobate waveguide in conjunction with a photon-echo quantum memory protocol4, and increase the spectral acceptance from the current maximum5 of 100 megahertz to 5 gigahertz. We assess the entanglement-preserving nature of our storage device through Bell inequality violations6 and by comparing the amount of entanglement contained in the detected photon pairs before and after the reversible transfer. These measurements show, within statistical error, a perfect mapping process. Our broadband quantum memory complements the family of robust, integrated lithium niobate devices7. It simplifies frequency-matching of light with matter interfaces in advanced applications of quantum communication, bringing fully quantum-enabled networks a step closer.

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Figure 1: Schematics of the experimental set-up.
Figure 2: The storage medium.
Figure 3: Measurement of density matrices.


  1. Lvovsky, A. I. & Sanders, B. C. &. Tittel, W. Optical quantum memory. Nature Photon. 3, 706–714 (2009)

    Article  ADS  CAS  Google Scholar 

  2. Sangouard, N., Simon, C., de Riedmatten, H. & Gisin, N. Quantum repeaters based on atomic ensembles and linear optics. Preprint at 〈〉 (2009)

  3. Kimble, H. J. The quantum Internet. Nature 453, 1023–1030 (2008)

    Article  ADS  CAS  Google Scholar 

  4. de Riedmatten, H., Afzelius, M., Staudt, M. U., Simon, C. & Gisin, N. A solid-state light–matter interface at the single-photon level. Nature 456, 773–777 (2008)

    Article  ADS  CAS  Google Scholar 

  5. Usmani, I., Afzelius, M., de Riedmatten, H. & Gisin, N. Mapping multiple photonic qubits into and out of one solid-state atomic ensemble. Nature Commun. 1, 1–7 (2010)

    Article  CAS  Google Scholar 

  6. Pan, J.-W., Chen, Z.-B., Żukowski, M., Weinfurter, H. & Zeilinger, A. Multi-photon entanglement and interferometry. Preprint at 〈〉 (2008)

  7. Sohler, W. et al. Integrated optical devices in lithium niobate. Opt. Photon. News 24–31. (January 2008)

  8. Gisin, N., Ribordy, G., Tittel, W. & Zbinden, H. Quantum cryptography. Rev. Mod. Phys. 74, 145–195 (2002)

    Article  ADS  Google Scholar 

  9. Julsgaard, B., Sherson, J. & Cirac, J. I. J. Fiurášek, J. & Polzik, E. S. Experimental demonstration of quantum memory for light. Nature 432, 482–486 (2004)

    Article  ADS  CAS  Google Scholar 

  10. Chanelière, T. et al. Storage and retrieval of single photons transmitted between remote quantum memories. Nature 438, 833–836 (2005)

    Article  ADS  Google Scholar 

  11. Eisaman, M. D. et al. Electromagnetically induced transparency with tunable single-photon pulses. Nature 438, 837–841 (2005)

    Article  ADS  CAS  Google Scholar 

  12. Honda, K. et al. Storage and retrieval of a squeezed vacuum. Phys. Rev. Lett. 100, 093601 (2008)

    Article  ADS  Google Scholar 

  13. Appel, J., Figueroa, E., Korystov, D., Lobino, M. & Lvovsky, A. Quantum memory for squeezed light. Phys. Rev. Lett. 100, 093602 (2008)

    Article  ADS  Google Scholar 

  14. Hedges, M. P., Longdell, J. J., Li, Y. & Sellars, M. J. Efficient quantum memory for light. Nature 465, 1052–1056 (2010)

    Article  ADS  CAS  Google Scholar 

  15. Boozer, A. D. et al. Reversible state transfer between light and a single trapped atom. Phys. Rev. Lett. 98, 193601 (2007)

    Article  ADS  CAS  Google Scholar 

  16. Choi, C. S. & Deng, H. Laurat, J. & Kimble, H. J. Mapping photonic entanglement into and out of a quantum memory. Nature 452, 67–71 (2008)

    Article  ADS  CAS  Google Scholar 

  17. Akiba, K. & Kashiwagi, K. Arikawa, M. & Kozuma, M. Storage and retrieval of non-classical photon pairs and conditional single photons generated by the parametric down-conversion process. N. J. Phys. 11, 013049 (2009)

    Article  Google Scholar 

  18. Jin, X.-M. et al. Quantum interface between frequency-uncorrelated down-converted entanglement and atomic-ensemble quantum memory. Preprint at 〈〉 (2010)

  19. Chou, C. W. et al. Measurement-induced entanglement for excitation stored in remote atomic ensembles. Nature 438, 828–832 (2005)

    Article  ADS  CAS  Google Scholar 

  20. Matsukevich, D. N. et al. Entanglement of a photon and a collective atomic excitation. Phys. Rev. Lett. 95, 040405 (2005)

    Article  ADS  CAS  Google Scholar 

  21. Yuan, Z.-S. et al. Experimental demonstration of a BDCZ quantum repeater node. Nature 454, 1098–1101 (2008)

    Article  ADS  CAS  Google Scholar 

  22. Blinov, B. B., Moehring, D. L., Duan, L.-M. & Monroe, C. Observation of entanglement between a single trapped atom and a single photon. Nature 428, 153–157 (2004)

    Article  ADS  CAS  Google Scholar 

  23. Togan, E. et al. Quantum entanglement between an optical photon and a solid-state spin qubit. Nature 466, 730–734 (2010)

    Article  ADS  CAS  Google Scholar 

  24. Longdell, J., Fraval, E., Sellars, M. & Manson, N. Stopped light with storage times greater than one second using electromagnetically induced transparency in a solid. Phys. Rev. Lett. 95, 063601 (2005)

    Article  ADS  CAS  Google Scholar 

  25. Marcikic, I. et al. Time-bin entangled qubits for quantum communication created by femtosecond pulses. Phys. Rev. A 66, 062308 (2002)

    Article  ADS  Google Scholar 

  26. Sinclair, N. et al. Spectroscopic investigations of a Ti:Tm:LiNbO3 waveguide for photon-echo quantum memory. J. Lumin. 130, 1586–1593 (2010)

    Article  CAS  Google Scholar 

  27. Altepeter, J. B. & Jeffrey, E. R. &. Kwiat, P. G. Photonic state tomography. Adv. At. Mol. Opt. Phys. 52, 105–159 (2005)

    Article  ADS  CAS  Google Scholar 

  28. Plenio, M. B. & Virmani, S. An introduction to entanglement measures. Quant. Inf. Comput. 7, 1–51 (2007)

    MathSciNet  MATH  Google Scholar 

  29. Clausen, C. et al. Quantum storage of photonic entanglement in a crystal. Nature 10.1038/nature09662 (this issue)

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This work is supported by NSERC, QuantumWorks, General Dynamics Canada, iCORE (now part of Alberta Innovates), CFI, AAET and FQRNT. We thank C. La Mela, T. Chanelière, T. Stuart, V. Kiselyov and C. Dascollas for help during various stages of the experiment, C. Simon, K. Rupavatharam and N. Gisin for discussions, and A. Lvovsky for lending us a single-photon detector.

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Authors and Affiliations



The Ti:Tm:LiNbO3 waveguide was fabricated and characterized at room temperature by M.G., R.R. and W.S. The photon-pair source was built by J.J., J.A.S. and F.B., the AFC memory set-up was developed by E.S. and N.S., and the complete experiment was conceived and directed by W.T. The measurements and the analysis were done by E.S., N.S., J.J., J.A.S., D.O. and W.T., and W.T., E.S., N.S., J.J., J.A.S. and D.O. wrote the paper. E.S., N.S., J.J. and J.A.S. contributed equally to this work.

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Correspondence to Wolfgang Tittel.

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The authors declare no competing financial interests.

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The file contains Supplementary Text and Data, Supplementary Tables 1-2, Supplementary Figure 1 with a legend and additional references. (PDF 317 kb)

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Saglamyurek, E., Sinclair, N., Jin, J. et al. Broadband waveguide quantum memory for entangled photons. Nature 469, 512–515 (2011).

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