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Scalable photonic network architecture based on motional averaging in room temperature gas.

Borregaard J, Zugenmaier M, Petersen JM, Shen H, Vasilakis G, Jensen K, Polzik ES, Sørensen AS - Nat Commun (2016)

Bottom Line: Thermal atomic vapours, which present a simple and scalable resource, have only been used for continuous variable processing or for discrete variable processing on short timescales where atomic motion is negligible.Here we develop a theory based on motional averaging to enable room temperature discrete variable quantum memories and coherent single-photon sources.We demonstrate the feasibility of this approach to scalable quantum memories with a proof-of-principle experiment with room temperature atoms contained in microcells with spin-protecting coating, placed inside an optical cavity.

View Article: PubMed Central - PubMed

Affiliation: The Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, Copenhagen Ø DK-2100, Denmark.

ABSTRACT
Quantum interfaces between photons and atomic ensembles have emerged as powerful tools for quantum technologies. Efficient storage and retrieval of single photons requires long-lived collective atomic states, which is typically achieved with immobilized atoms. Thermal atomic vapours, which present a simple and scalable resource, have only been used for continuous variable processing or for discrete variable processing on short timescales where atomic motion is negligible. Here we develop a theory based on motional averaging to enable room temperature discrete variable quantum memories and coherent single-photon sources. We demonstrate the feasibility of this approach to scalable quantum memories with a proof-of-principle experiment with room temperature atoms contained in microcells with spin-protecting coating, placed inside an optical cavity. The experimental conditions correspond to a few photons per pulse and a long coherence time of the forward scattered photons is demonstrated, which is the essential feature of the motional averaging.

No MeSH data available.


Related in: MedlinePlus

Write and read efficiency.(a) Write efficiency as a function of the linewidth of the filter cavity κ2. We have simulated a Cs-cell with wall length 2L=300 μm and cavity beam waist w=55 μm corresponding to the cells being used in the proof-of-principle experiment. We have assumed a detuning of Δ∼2π·900 MHz, a pulse length of tint=10/κ2 and a cell-cavity decay rate κ1=2π·46 MHz. (b) Optimal readout efficiency as a function of the readout time τread without the filter cavity (corresponding to κ2→∞). The efficiency was simulated for the same Cs-cells as the write efficiency and we have assumed that  where Γread is the readout rate, which is proportional to the classical drive intensity. The optical depth was assumed to be 168 as measured in the experiment. The finesse of the filter cavity was varied between 20 and 100 to get the optimal readout efficiency. We have included the full-level structure of 133Cs in the simulations (see Supplementary Methods and Supplementary Fig. 4).
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f3: Write and read efficiency.(a) Write efficiency as a function of the linewidth of the filter cavity κ2. We have simulated a Cs-cell with wall length 2L=300 μm and cavity beam waist w=55 μm corresponding to the cells being used in the proof-of-principle experiment. We have assumed a detuning of Δ∼2π·900 MHz, a pulse length of tint=10/κ2 and a cell-cavity decay rate κ1=2π·46 MHz. (b) Optimal readout efficiency as a function of the readout time τread without the filter cavity (corresponding to κ2→∞). The efficiency was simulated for the same Cs-cells as the write efficiency and we have assumed that where Γread is the readout rate, which is proportional to the classical drive intensity. The optical depth was assumed to be 168 as measured in the experiment. The finesse of the filter cavity was varied between 20 and 100 to get the optimal readout efficiency. We have included the full-level structure of 133Cs in the simulations (see Supplementary Methods and Supplementary Fig. 4).

Mentions: To describe the write efficiency quantitatively, we have numerically simulated the experiment with Cs-cells including the full-level structure of the atoms as described in Supplementary Methods. The Λ-scheme level structure can be realized with the two ground states /0〉=/F=4, mF=4〉 and /1〉=/F=3, mF=3〉 in the 62S1/2 ground-state manifold and the excited state /e〉=/F′=4, mF′=4〉 in the excited 62P3/2 manifold. Note that with this configuration, the quantum and classical field differ both in polarization and frequency and the filtering of the quantum photon is thus expected to be easily obtained using a combination of both polarization filtering and the filter cavity. Figure 3a shows the simulated write efficiency as a function of κ2. It is seen that ηwrite≈90% for κ2≈2π·10 kHz, which translates into a write time of ∼160 μs. Furthermore, we estimate that the number of classical photons, which should be filtered from the quantum photon is ∼4.4 × 105 for realistic experimental parameters (see Supplementary Methods). This level of filtering is expected to be easily achieved using frequency filtering.


Scalable photonic network architecture based on motional averaging in room temperature gas.

Borregaard J, Zugenmaier M, Petersen JM, Shen H, Vasilakis G, Jensen K, Polzik ES, Sørensen AS - Nat Commun (2016)

Write and read efficiency.(a) Write efficiency as a function of the linewidth of the filter cavity κ2. We have simulated a Cs-cell with wall length 2L=300 μm and cavity beam waist w=55 μm corresponding to the cells being used in the proof-of-principle experiment. We have assumed a detuning of Δ∼2π·900 MHz, a pulse length of tint=10/κ2 and a cell-cavity decay rate κ1=2π·46 MHz. (b) Optimal readout efficiency as a function of the readout time τread without the filter cavity (corresponding to κ2→∞). The efficiency was simulated for the same Cs-cells as the write efficiency and we have assumed that  where Γread is the readout rate, which is proportional to the classical drive intensity. The optical depth was assumed to be 168 as measured in the experiment. The finesse of the filter cavity was varied between 20 and 100 to get the optimal readout efficiency. We have included the full-level structure of 133Cs in the simulations (see Supplementary Methods and Supplementary Fig. 4).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4834638&req=5

f3: Write and read efficiency.(a) Write efficiency as a function of the linewidth of the filter cavity κ2. We have simulated a Cs-cell with wall length 2L=300 μm and cavity beam waist w=55 μm corresponding to the cells being used in the proof-of-principle experiment. We have assumed a detuning of Δ∼2π·900 MHz, a pulse length of tint=10/κ2 and a cell-cavity decay rate κ1=2π·46 MHz. (b) Optimal readout efficiency as a function of the readout time τread without the filter cavity (corresponding to κ2→∞). The efficiency was simulated for the same Cs-cells as the write efficiency and we have assumed that where Γread is the readout rate, which is proportional to the classical drive intensity. The optical depth was assumed to be 168 as measured in the experiment. The finesse of the filter cavity was varied between 20 and 100 to get the optimal readout efficiency. We have included the full-level structure of 133Cs in the simulations (see Supplementary Methods and Supplementary Fig. 4).
Mentions: To describe the write efficiency quantitatively, we have numerically simulated the experiment with Cs-cells including the full-level structure of the atoms as described in Supplementary Methods. The Λ-scheme level structure can be realized with the two ground states /0〉=/F=4, mF=4〉 and /1〉=/F=3, mF=3〉 in the 62S1/2 ground-state manifold and the excited state /e〉=/F′=4, mF′=4〉 in the excited 62P3/2 manifold. Note that with this configuration, the quantum and classical field differ both in polarization and frequency and the filtering of the quantum photon is thus expected to be easily obtained using a combination of both polarization filtering and the filter cavity. Figure 3a shows the simulated write efficiency as a function of κ2. It is seen that ηwrite≈90% for κ2≈2π·10 kHz, which translates into a write time of ∼160 μs. Furthermore, we estimate that the number of classical photons, which should be filtered from the quantum photon is ∼4.4 × 105 for realistic experimental parameters (see Supplementary Methods). This level of filtering is expected to be easily achieved using frequency filtering.

Bottom Line: Thermal atomic vapours, which present a simple and scalable resource, have only been used for continuous variable processing or for discrete variable processing on short timescales where atomic motion is negligible.Here we develop a theory based on motional averaging to enable room temperature discrete variable quantum memories and coherent single-photon sources.We demonstrate the feasibility of this approach to scalable quantum memories with a proof-of-principle experiment with room temperature atoms contained in microcells with spin-protecting coating, placed inside an optical cavity.

View Article: PubMed Central - PubMed

Affiliation: The Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, Copenhagen Ø DK-2100, Denmark.

ABSTRACT
Quantum interfaces between photons and atomic ensembles have emerged as powerful tools for quantum technologies. Efficient storage and retrieval of single photons requires long-lived collective atomic states, which is typically achieved with immobilized atoms. Thermal atomic vapours, which present a simple and scalable resource, have only been used for continuous variable processing or for discrete variable processing on short timescales where atomic motion is negligible. Here we develop a theory based on motional averaging to enable room temperature discrete variable quantum memories and coherent single-photon sources. We demonstrate the feasibility of this approach to scalable quantum memories with a proof-of-principle experiment with room temperature atoms contained in microcells with spin-protecting coating, placed inside an optical cavity. The experimental conditions correspond to a few photons per pulse and a long coherence time of the forward scattered photons is demonstrated, which is the essential feature of the motional averaging.

No MeSH data available.


Related in: MedlinePlus