Fidelity of photon propagation in electromagnetically induced transparency in the presence of four-wave mixing

Lauk, Nikolai; O’Brien, Christopher; Fleischhauer, Michael

doi:10.1103/physreva.88.013823

Cited by 69 publications

(64 citation statements)

References 23 publications

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“…Following the treatment in [24,31] for the double-Λ scheme in the approximation of negligible spin coherence relaxation rate (γ gs = 0, ), the output fields can approximately be expressed for resonant fieldŝ…”

Section: Theorymentioning

confidence: 99%

Suppression of the four-wave mixing amplification via Raman absorption

Romanov

O’Brien

Novikova

2016

Journal of Modern Optics

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We propose a method to controllably suppress the effect of the four-wave mixing caused by the coupling of the strong control optical field to both optical transitions in the Λ system under the conditions of electromagnetically induced transparency. At sufficiently high atomic density, this process leads to amplification of a weak optical signal field, that is detrimental for the fidelity of any EIT-based quantum information applications. Here we show that an additional absorption resonance centered around the idler field frequency, generated in such a four-wave mixing process, may efficiently suppress the unwanted signal amplification without affecting properties of the EIT interaction. We discuss the possibility of creating such tunable absorption using two-photon Raman absorption resonances in the other Rb isotope, and present some preliminary experimental results.

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Section: Theorymentioning

confidence: 99%

Suppression of the four-wave mixing amplification via Raman absorption

Romanov

O’Brien

Novikova

2016

Journal of Modern Optics

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“…There it was found that while fluorescence noise was negligible for off-resonant storage of short pulses, the thermal noise contributed by four-wave mixing destroyed the anti-bunching characteristic of single photons. Fourwave mixing noise is therefore the key roadblock preventing the implementation of Λ-memories at room temperature [27,28]. Suggested solutions to this problem include partial suppression via polarisation selection rules [29], and engineering a Raman absorption feature in an isotopically mixed vapour [30].…”

Section: Introductionmentioning

confidence: 99%

Theory of noise suppression inΛ-type quantum memories by means of a cavity

et al. 2017

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Quantum memories, capable of storing single photons or other quantum states of light, to be retrieved on-demand, offer a route to large-scale quantum information processing with light. A promising class of memories is based on far-off-resonant Raman absorption in ensembles of Λ-type atoms. However at room temperature these systems exhibit unwanted four-wave mixing, which is prohibitive for applications at the single-photon level. Here we show how this noise can be suppressed by placing the storage medium inside a moderate-finesse optical cavity, thereby removing the main roadblock hindering this approach to quantum memory.

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“…However, large control pulse energies are needed to drive the storage interaction far from resonance, and the control can also drive unwanted four-wave mixing, introducing noise which cannot be filtered out either spectrally or temporally. Four-wave mixing noise has emerged as the last remaining roadblock to the development of efficient Λ-type room-temperature quantum memories [17,[20][21][22][23]. We solve this problem by introducing a new cavity enhanced Raman memory protocol.…”

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confidence: 99%

A Cavity-Enhanced Room-Temperature Broadband Raman Memory

Ledingham¹,

Munns²,

Thomas³

et al. 2016

Conference on Lasers and Electro-Optics

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Broadband quantum memories hold great promise as multiplexing elements in future photonic quantum information protocols. Alkali vapour Raman memories combine high-bandwidth storage, on-demand read-out, and operation at room temperature without collisional fluorescence noise. However, previous implementations have required large control pulse energies and suffered from fourwave mixing noise. Here we present a Raman memory where the storage interaction is enhanced by a low-finesse birefringent cavity tuned into simultaneous resonance with the signal and control fields, dramatically reducing the energy required to drive the memory. By engineering anti-resonance for the anti-Stokes field, we also suppress the four-wave mixing noise and report the lowest unconditional noise floor yet achieved in a Raman-type warm vapour memory, (15 ± 2) × 10 −3 photons per pulse, with a total efficiency of (9.5 ± 0.5)%. Quantum information technologies such as quantum key distribution and random number generators are beginning to transition into the commercial sphere, where key requirements are the ability to function at high speed, and in non-laboratory settings. The high carrier frequency of optical signals enables photonic quantum devices to operate noise-free at room temperature whilst offering GHz-THz operational bandwidths. However, direct photon-photon interactions are prohibitively weak, which has held back the development of photonic quantum processors. One solution to this problem has been to use probabilistic measurement-induced non-linearities [1], but the probability of success decreases exponentially with system size, limiting the state of the art to < 10 photons [2]. Further scaling photonic devices requires a multiplexing strategy. Quantum memories capable of storing photons and releasing them on-demand provide the ability to temporally multiplex a repeat-until-success architecture to achieve a freely scalable photonic quantum information platform operable at room temperature.There are many types of quantum memory for light under development: electromagnetically induced transparency [3], the full atomic-frequency comb protocol [4,5], gradient-echo memories [6,7], and the far-offresonant Raman memory [8,9]. Each of these protocols have advantages and challenges, see Ref.[10] for a recent review. A helpful metric for temporal multiplexing is the time-bandwidth product B = τ δ, with δ the acceptance bandwidth and τ the memory lifetime. B is the maximum number of time-bins over which a memory can synchronise an input signal. Time-bandwidth products of B > 1000 enable a dramatic enhancement in the multiphoton rate from parametric photon sources [11], as required to utilise multiphoton interference for computational speed-up (e.g. boson sampling [12]). Large timebandwidth products have been achieved with cold atom memories [13,14], cryogenic rare earth ion memories [15] and room-temperature Raman memories [8,16]. In this paper we present an implementation of an alkali-vapour Raman memory, operating at 75• C, and show the lo...

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Fidelity of photon propagation in electromagnetically induced transparency in the presence of four-wave mixing

Cited by 69 publications

References 23 publications

Suppression of the four-wave mixing amplification via Raman absorption

Suppression of the four-wave mixing amplification via Raman absorption

Theory of noise suppression inΛ-type quantum memories by means of a cavity

A Cavity-Enhanced Room-Temperature Broadband Raman Memory

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