Storage and Retrieval of THz-Bandwidth Single Photons Using a Room-Temperature Diamond Quantum Memory

We propose two compact, economic, and scalable schemes for implementing optical controlled-phase-flip and controlled-controlled-phase-flip gates by using the input-output process of a single-sided cavity strongly coupled to a single nitrogen-vacancy-center defect in diamond. Additional photonic qubits, necessary for procedures based on the parity-check measurement or controlled-path and merging gates, are not employed in our schemes. In the controlled-path gate, the paths of the target photon are conditionally controlled by the control photon, and these two paths can be merged back into one by using a merging gate. Only one half-wave plate is employed in our scheme for the controlled-phase-flip gate. Compared with the conventional synthesis procedures for constructing a controlled-controlled-phase-flip gate, the cost of which is two controlled-path gates and two merging gates, or six controlled-NOT gates, our scheme is more compact and simpler. Our schemes could be performed with a high fidelity and high efficiency with current achievable experimental techniques.

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“…1(b)]. The coupling between a single photon and an NV electron spin has been experimentally demonstrated [43,50,63].…”

Section: A a Single Nv Center Coupled To A Single-sided Optical Resomentioning

confidence: 99%

Universal photonic quantum gates assisted by ancilla diamond nitrogen-vacancy centers coupled to resonators

Wei

Long

2015

Phys. Rev. A

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“…Optical quantum memories are one of the primary goals of this development, and their applications [1,2] are likely to extend beyond their role in quantum repeaters [3]. Many recent efforts have been devoted to their implementation in atomic ensembles [4], and in particular, memories compatible with ultrafast light are desirable for their large time-bandwidth products and fast operational speeds [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Optical quantum memory for ultrafast photons using molecular alignment

Thekkadath

Heshami

England

et al. 2016

Journal of Modern Optics

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The absorption of broadband photons in atomic ensembles requires either an effective broadening of the atomic transition linewidth, or an off-resonance Raman interaction. Here we propose a scheme for a quantum memory capable of storing and retrieving ultrafast photons in an ensemble of twolevel atoms by using a propagation medium with a time-dependent refractive index generated from aligning an ensemble of gas-phase diatomic molecules. The refractive index dynamics generates an effective longitudinal inhomogeneous broadening of the two-level transition. We numerically demonstrate this scheme for storage and retrieval of a weak pulse as short as 50 fs, with a storage time of up to 20 ps. With additional optical control of the molecular alignment dynamics, the storage time can be extended about one nanosecond leading to time-bandwidth products of order 104 . This scheme could in principle be achieved using either a hollow-core fiber or a high-pressure gas cell, in a gaseous host medium comprised of diatomic molecules and a two-level atomic vapor at room temperature.

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“…However, for alkali atoms this is not possible due to destructive interference between interaction pathways associated with different intermediate excited states |2 [22]. Four-wave mixing can also be suppressed in dispersive media where it is poorly phasematched [9,18], but the Stokes shift ∆ HF in alkali vapours is not large enough to introduce a significant phase mismatch. A third approach towards suppressing four-wave mixing is the creation of a second Raman absorption feature at the anti-stokes frequency [30].…”

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confidence: 99%

“…The absorption linewidth of the fielddressed atoms can be made broadband with a pulsed control [16], enabling a large time-bandwidth product even with ∼ µs coherence times in a room-temperature vapour [8], and allowing direct interfacing with pulsed heralded photon sources [17,18]. Operation with temporally short and far-detuned pulses also removes contamination of the retrieved signals by collision-induced fluorescence [19].…”

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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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Storage and Retrieval of THz-Bandwidth Single Photons Using a Room-Temperature Diamond Quantum Memory

Cited by 117 publications

References 33 publications

Universal photonic quantum gates assisted by ancilla diamond nitrogen-vacancy centers coupled to resonators

Universal photonic quantum gates assisted by ancilla diamond nitrogen-vacancy centers coupled to resonators

Optical quantum memory for ultrafast photons using molecular alignment

A Cavity-Enhanced Room-Temperature Broadband Raman Memory

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