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High efficiency coherent optical memory with warm rubidium vapour.

Hosseini M, Sparkes BM, Campbell G, Lam PK, Buchler BC - Nat Commun (2011)

Bottom Line: Here, we present results from a coherent optical memory based on warm rubidium vapour and show 87% efficient recall of light pulses, the highest efficiency measured to date for any coherent optical memory suitable for quantum information applications.We also show storage and recall of up to 20 pulses from our system.These results show that simple warm atomic vapour systems have clear potential as a platform for quantum memory.

View Article: PubMed Central - PubMed

Affiliation: ARC Centre of Excellence for Quantum Atom Optics, Department of Quantum Science, The Australian National University, Canberra, ACT 0200, Australia.

ABSTRACT
By harnessing aspects of quantum mechanics, communication and information processing could be radically transformed. Promising forms of quantum information technology include optical quantum cryptographic systems and computing using photons for quantum logic operations. As with current information processing systems, some form of memory will be required. Quantum repeaters, which are required for long distance quantum key distribution, require quantum optical memory as do deterministic logic gates for optical quantum computing. Here, we present results from a coherent optical memory based on warm rubidium vapour and show 87% efficient recall of light pulses, the highest efficiency measured to date for any coherent optical memory suitable for quantum information applications. We also show storage and recall of up to 20 pulses from our system. These results show that simple warm atomic vapour systems have clear potential as a platform for quantum memory.

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Results of 20 pulse storage and frequency shifting.(a) Amplitude of 20 Gaussian input (black) and echo pulses (red) with total recall efficiency of 2%. (b) The input pulse (black) is stored and recalled with an introduced offset to the magnetic field gradient. The red curve denotes the straight transmitted pulse and the recall pulse. The interference pattern shows that the pulse is coherent with the original light field and is shifted by 600 kHz.
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f3: Results of 20 pulse storage and frequency shifting.(a) Amplitude of 20 Gaussian input (black) and echo pulses (red) with total recall efficiency of 2%. (b) The input pulse (black) is stored and recalled with an introduced offset to the magnetic field gradient. The red curve denotes the straight transmitted pulse and the recall pulse. The interference pattern shows that the pulse is coherent with the original light field and is shifted by 600 kHz.

Mentions: In Figure 3a, we show the storage and recall of 20 Gaussian pulses with an overall efficiency of 2%. For this experiment, the control field power was reduced from 370 to 64 mW to reduce the decay rate of the memory. The lower optical depth in this case limits the efficiency of the storage and recall. From this data we can infer a delay-bandwidth product24 of ~40 for the our memory. This is comparable to a recent demonstration of 64 pulses delayed using AFC with efficiency of 1.3% (ref. 25). Figure 3b demonstrates frequency shifted recall of a pulse16. This was achieved by applying an offset magnetic field after the magnetic field gradient was flipped to increase the splitting of the atomic ground states. On recall, the pulse is shifted by the added splitting, which in this case is 600 kHz, as seen by the interference fringes in the heterodyne signal. The presence of interference fringes proves the coherent recall of our memory.


High efficiency coherent optical memory with warm rubidium vapour.

Hosseini M, Sparkes BM, Campbell G, Lam PK, Buchler BC - Nat Commun (2011)

Results of 20 pulse storage and frequency shifting.(a) Amplitude of 20 Gaussian input (black) and echo pulses (red) with total recall efficiency of 2%. (b) The input pulse (black) is stored and recalled with an introduced offset to the magnetic field gradient. The red curve denotes the straight transmitted pulse and the recall pulse. The interference pattern shows that the pulse is coherent with the original light field and is shifted by 600 kHz.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3105315&req=5

f3: Results of 20 pulse storage and frequency shifting.(a) Amplitude of 20 Gaussian input (black) and echo pulses (red) with total recall efficiency of 2%. (b) The input pulse (black) is stored and recalled with an introduced offset to the magnetic field gradient. The red curve denotes the straight transmitted pulse and the recall pulse. The interference pattern shows that the pulse is coherent with the original light field and is shifted by 600 kHz.
Mentions: In Figure 3a, we show the storage and recall of 20 Gaussian pulses with an overall efficiency of 2%. For this experiment, the control field power was reduced from 370 to 64 mW to reduce the decay rate of the memory. The lower optical depth in this case limits the efficiency of the storage and recall. From this data we can infer a delay-bandwidth product24 of ~40 for the our memory. This is comparable to a recent demonstration of 64 pulses delayed using AFC with efficiency of 1.3% (ref. 25). Figure 3b demonstrates frequency shifted recall of a pulse16. This was achieved by applying an offset magnetic field after the magnetic field gradient was flipped to increase the splitting of the atomic ground states. On recall, the pulse is shifted by the added splitting, which in this case is 600 kHz, as seen by the interference fringes in the heterodyne signal. The presence of interference fringes proves the coherent recall of our memory.

Bottom Line: Here, we present results from a coherent optical memory based on warm rubidium vapour and show 87% efficient recall of light pulses, the highest efficiency measured to date for any coherent optical memory suitable for quantum information applications.We also show storage and recall of up to 20 pulses from our system.These results show that simple warm atomic vapour systems have clear potential as a platform for quantum memory.

View Article: PubMed Central - PubMed

Affiliation: ARC Centre of Excellence for Quantum Atom Optics, Department of Quantum Science, The Australian National University, Canberra, ACT 0200, Australia.

ABSTRACT
By harnessing aspects of quantum mechanics, communication and information processing could be radically transformed. Promising forms of quantum information technology include optical quantum cryptographic systems and computing using photons for quantum logic operations. As with current information processing systems, some form of memory will be required. Quantum repeaters, which are required for long distance quantum key distribution, require quantum optical memory as do deterministic logic gates for optical quantum computing. Here, we present results from a coherent optical memory based on warm rubidium vapour and show 87% efficient recall of light pulses, the highest efficiency measured to date for any coherent optical memory suitable for quantum information applications. We also show storage and recall of up to 20 pulses from our system. These results show that simple warm atomic vapour systems have clear potential as a platform for quantum memory.

Show MeSH
Related in: MedlinePlus