| 1. |
- Afzelius, Mikael, et al.
(författare)
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Demonstration of Atomic Frequency Comb Memory for Light with Spin-Wave Storage
- 2010
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Ingår i: Physical Review Letters. - 1079-7114. ; 104:4
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Tidskriftsartikel (refereegranskat)abstract
- We present a light-storage experiment in a praseodymium-doped crystal where the light is mapped onto an inhomogeneously broadened optical transition shaped into an atomic frequency comb. After absorption of the light, the optical excitation is converted into a spin-wave excitation by a control pulse. A second control pulse reads the memory (on-demand) by reconverting the spin-wave excitation to an optical one, where the comb structure causes a photon-echo-type rephasing of the dipole moments and directional retrieval of the light. This combination of photon-echo and spin-wave storage allows us to store submicrosecond (450 ns) pulses for up to 20 mu s. The scheme has a high potential for storing multiple temporal modes in the single-photon regime, which is an important resource for future long-distance quantum communication based on quantum repeaters.
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| 2. |
- Amari, Atia, et al.
(författare)
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Towards an efficient atomic frequency comb quantum memory
- 2010
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Ingår i: Journal of Luminescence. - : Elsevier BV. - 0022-2313. ; 130:9, s. 1579-1585
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Konferensbidrag (refereegranskat)abstract
- We present an efficient photon-echo experiment based on atomic frequency combs [Phys. Rev. A 79 (2009) 052329]. Echoes containing an energy of up to 35% of that of the input pulse are observed in a Pr3+ -doped Y2SiO5 crystal. This material allows for the precise spectral holeburning needed to make a sharp and highly absorbing comb structure. We compare our results with a simple theoretical model with satisfactory agreement. Our results show that atomic frequency combs has the potential for high-efficiency storage of single photons as required in future long-distance communication based on quantum repeaters. (c) 2010 Elsevier B.V. All rights reserved.
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| 3. |
- Lovric, Marko, et al.
(författare)
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Hyperfine characterization and spin coherence lifetime extension in Pr3+:La-2(WO4)(3)
- 2011
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Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 84:10
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Tidskriftsartikel (refereegranskat)abstract
- Rare-earth ions in dielectric crystals are interesting candidates for storing quantum states of photons. A limiting factor on the optical density and thus the conversion efficiency is the distortion introduced in the crystal by doping elements of one type into a crystal matrix of another type. Here we investigate the system Pr3+:La-2(WO4)(3), where the similarity of the ionic radii of Pr and La minimizes distortions due to doping. We characterize the praseodymium hyperfine interaction of the ground-state (H-3(4)) and one excited state (D-1(2)) and determine the spin Hamiltonian parameters by numerical analysis of Raman-heterodyne spectra, which were collected for a range of static external magnetic-field strengths and orientations. On the basis of a crystal-field analysis, we discuss the physical origin of the experimentally determined quadrupole and Zeeman tensor characteristics. We show the potential for quantum memory applications by measuring the spin coherence lifetime in a magnetic field that is chosen such that additional magnetic fields do not shift the transition frequency in first order. Experimental results demonstrate a spin coherence lifetime of 158 ms - almost 3 orders of magnitude longer than in zero field.
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| 4. |
- Sabooni, Mahmood, et al.
(författare)
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Cavity-enhanced storage-preparing for high-efficiency quantum memories
- 2013
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Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Cavity-assisted quantum memory storage has been proposed for creating efficient (close to unity) quantum memories using weakly absorbing materials. Using this approach, we experimentally demonstrate a significant (similar to 20-fold) enhancement in quantum memory efficiency compared to the no cavity case. A strong dispersion originating from absorption engineering inside the cavity was observed, which directly affects the cavity line width. A more than three orders of magnitude reduction of cavity mode spacing and cavity line width from GHz to MHz was observed. We are not aware of any previous observation of several orders of magnitude cavity mode spacing and cavity line width reduction due to slow light effects.
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| 5. |
- Sabooni, Mahmood, et al.
(författare)
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Efficient Quantum Memory Using a Weakly Absorbing Sample
- 2013
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Ingår i: Physical Review Letters. - 1079-7114. ; 110:13
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Tidskriftsartikel (refereegranskat)abstract
- A light-storage experiment with a total (storage and retrieval) efficiency eta = 56% is carried out by enclosing a sample, with a single-pass absorption of 10%, in an impedance-matched cavity. The experiment is carried out using the atomic frequency comb (AFC) technique in a praseodymium-doped crystal (0: 05% Pr3+: Y2SiO5) and the cavity is created by depositing reflection coatings directly onto the crystal surfaces. The AFC technique has previously by far demonstrated the highest multimode capacity of all quantum memory concepts tested experimentally. We claim that the present work shows that it is realistic to create efficient, on-demand, long storage time AFC memories. DOI: 10.1103/PhysRevLett.110.133604
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| 6. |
- Sabooni, Mahmood, et al.
(författare)
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Spectral Engineering of Slow Light, Cavity Line Narrowing, and Pulse Compression
- 2013
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Ingår i: Physical Review Letters. - 1079-7114. ; 111:18
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Tidskriftsartikel (refereegranskat)abstract
- More than 4 orders of magnitude of cavity-linewidth narrowing in a rare-earth-ion-doped crystal cavity, emanating from strong intracavity dispersion caused by off-resonant interaction with dopant ions, is demonstrated. The dispersion profiles are engineered using optical pumping techniques creating significant semipermanent but reprogrammable changes of the rare-earth absorption profiles. Several cavity modes are shown within the spectral transmission window. Several possible applications of this phenomenon are discussed.
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| 7. |
- Sabooni, Mahmood, et al.
(författare)
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Storage and Recall of Weak Coherent Optical Pulses with an Efficiency of 25%
- 2010
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Ingår i: Physical Review Letters. - 1079-7114. ; 105:6
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate experimentally an efficient coherent rephasing scheme for the storage and recall of weak coherent light pulses in an inhomogeneously broadened optical transition in a Pr3+: YSO crystal at 2.1 K. Precise optical pumping using a frequency stable (approximate to 1 kHz linewidth) laser is employed to create a highly controllable atomic frequency comb structure. We report single photon level storage and retrieval efficiencies of 25%, based on coherent photon-echo-type reemission in the forward direction. The high efficiency is mainly a product of our highly controllable and precise ensemble-shaping technique. The coherence property of the quantum memory is proved through interference between a super-Gaussian pulse and the emitted echo.
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| 8. |
- Serrano, Diana, et al.
(författare)
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Impact of the ion-ion energy transfer on quantum computing schemes in rare-earth doped solids
- 2014
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Ingår i: Journal of Luminescence. - : Elsevier BV. - 0022-2313. ; 151, s. 93-99
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Tidskriftsartikel (refereegranskat)abstract
- We analyze the Ce3+-Pr3+:Y2SiO5 emission spectra obtained under selective excitation of the two Ce3+ sites in Y2SiO5 and we show clear evidence of direct energy transfer from Ce3+ to Pr3+. Energy transfer microparameters were calculated from the experimental spectral overlap between the Ce3+ emission and the Pr3+ and Eu3+ absorptions from which, the transfer mechanisms Ce3+-> Pr3+ are concluded to be more efficient than the transfer mechanisms Ce3+-> Eu3+. The energy transfer processes demonstrated here are potentially detrimental for an efficient qubit readout, using Ce3+ as readout ion, as they lead to a quenching of the Ce3+ luminescence and can give rise to the unwanted change of Pr3+ and Eu3+ qubit states. The quantum computing readout scheme is based on permanent electric dipole interactions scaling as R-3, where R is the distance between the Ce3+ and the qubit ion. The non-radiative energy transfer processes also depend on the ion-ion distances, however as R-6. A discussion about the microscopic dopant distributions leading to an efficient single-ion readout quantum computing scheme is here presented. The likely existence of energy transfer paths between the qubits or, as in this case, between the readout ion and the qubit ions, has not been taken into account so far by the rare-earth based quantum computing approaches. The results of this study suggest the need to consider them in order to design realistic and efficient quantum computing schemes for rare-earth doped solids. (C) 2014 Elsevier B.V. All rights reserved.
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| 9. |
- Simon, C., et al.
(författare)
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Quantum memories
- 2010
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Ingår i: European Physical Journal D. Atomic, Molecular, Optical and Plasma Physics. - : Springer Science and Business Media LLC. - 1434-6060. ; 58:1, s. 1-22
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Tidskriftsartikel (refereegranskat)abstract
- We perform a review of various approaches to the implementation of quantum memories, with an emphasis on activities within the quantum memory sub-project of the EU integrated project "Qubit Applications". We begin with a brief overview over different applications for quantum memories and different types of quantum memories. We discuss the most important criteria for assessing quantum memory performance and the most important physical requirements. Then we review the different approaches represented in "Qubit Applications" in some detail. They include solid-state atomic ensembles, NV centers, quantum dots, single atoms, atomic gases and optical phonons in diamond. We compare the different approaches using the discussed criteria.
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| 10. |
- Tittel, Wolfgang, et al.
(författare)
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Photon-echo quantum memory in solid state systems
- 2010
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Ingår i: Laser & Photonics Reviews. - : Wiley. - 1863-8880 .- 1863-8899. ; 4:2, s. 244-267
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Forskningsöversikt (refereegranskat)abstract
- Many applications of quantum communication crucially depend oil reversible transfer of quantum states between light and matter Motivated by rapid recent developments in theory and experiment, we review research related to quantum memory based oil a photon-echo approach in solid state material with emphasis on use in a quantum repeater After introducing quantum communication, the quantum repeater concept. and properties of a quantum memory required to be useful in a quantum repeater, we describe the historical development from spin echoes, discovered in 1950. to photon-echo quantum memory We present a simple theoretical description of the ideal protocol, and comment oil the impact of a non-ideal realization Oil Its quantum nature We extensively discuss rare-earth-ion doped crystals and glasses as material candidates, elaborate oil traditional photon-echo experiments as a test-bed for quantum State storage, and describe the current state-of-the-art of photon-echo quantum memory Finally, we give a brief outlook On Current research.
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