Precision spectral manipulation: A demonstration using a coherent optical memory

Sparkes, B. M.; Cairns, C.; Hosseini, Mahdi; Higginbottom, Daniel; Campbell, Geoff; Lam, Ping Koy; Buchler, Benjamin

doi:10.1063/1.4903159

Cited by 3 publications

(3 citation statements)

References 6 publications

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“…Moreover, the storage of multiple modes was shown to preserve optical coherence [5]. Due to the Fourier decomposition present in a GEM, recalls involving re-sequencing and spectral filtering of multiple modes within a single memory can be also achieved [6].…”

Section: Gradient Echo Memorymentioning

confidence: 99%

Quantum Nonlinear Optics Using Optical Memory

et al. 2013

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Large nonlinearity at the single-photon level can pave the way for the implementation of universal quantum gates. However, realizing large and noiseless nonlinearity at such low light levels has been a great challenge for scientists in the past decade. We present a proposal for using quantum memory to enhance the cross-phase modulation (XPM) of two optical fields. Our memory, which is based on the gradient echo memory (GEM) scheme, maps the optical fields into Fourier transformed polaritonic excitations in an atomic ensemble. We show that nonlinear interactions can be induced in GEM. Due to the slowing down and subsequent storage of light fields within a memory, nonlinear interaction time between the fields can be extended resulting in an enhancement of the effective nonlinearity. We present results showing noiseless cross-phase modulations and discuss plans to further increase the cross-phase modulation strength to a level useful for implementing quantum gates.

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Section: Gradient Echo Memorymentioning

confidence: 99%

Quantum Nonlinear Optics Using Optical Memory

et al. 2013

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“…With the forward-propagating control field present, an incoming forward-propagating probe field will be coherently scattered into a spinwave excitation at a longitudinal location that is determined by the probe frequency. The spatial profile of the stored spinwave will thus be given by the Fourier transform of the input probe pulse [40,41].…”

Section: Theorymentioning

confidence: 99%

Dynamical observations of self-stabilizing stationary light

Everett¹,

Campbell²,

Cho³

et al. 2016

Nature Phys

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Precise control of atom-light interactions is vital to many quantum information protocols. In particular, atomic systems can be used to slow and store light to form a quantum memory. Optical storage can be achieved via stopped light, where no optical energy remains in the atoms, or as stationary light, where some optical energy remains present during storage. In this work, we demonstrate a form of self-stabilising stationary light. From any initial state, our atom-light system evolves to a stable configuration that is devoid of coherent emission from the atoms, yet may contain bright optical excitation. This phenomenon is verified experimentally in a cloud of cold Rb87 atoms. The spinwave in our atomic cloud is imaged from the side allowing direct comparison with theoretical predictions.Coherent atom light interactions lie at the heart of many quantum information systems [1, 2]. In particular, implementations of quantum repeaters will likely rely on mapping of photonic states onto atomic systems to enable storage of quantum information [3,4]. Deterministic quantum logic gates in optical systems may also rely on atomic state mapping to enable nonlinear photon-photon interactions [5,6,7,8,9]. A fundamental issue facing any attempt to implement nonlinear cross phase modulation (XPM) is that the interaction is inherently very weak. Techniques are therefore required to increase the interaction time or interaction strength to allow useful amounts of phase shift. Interaction strength can be scaled up by choosing a nonlinear medium with strong optical interactions, such as Rydberg atoms [10,11]. A more general approach that works for any medium is to use smaller interaction volumes, since this increases the electric field per photon, and longer interaction times, which may be achieved by using an 1 arXiv:1609.08287v1 [quant-ph]

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“…Simple manipulation of these currents allows for fine tuning of the retrieved pulse. More complex spectral manipulations (such as those outlined in 29 ) can be done using a more advanced coil setup where the gradient along the memory can be tuned as a function of position and time independently. …”

Section: Pulse Storagementioning

confidence: 99%

Gradient Echo Quantum Memory in Warm Atomic Vapor

Pinel

Hosseini

Sparkes

et al. 2013

JoVE

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Gradient echo memory (GEM) is a protocol for storing optical quantum states of light in atomic ensembles. The primary motivation for such a technology is that quantum key distribution (QKD), which uses Heisenberg uncertainty to guarantee security of cryptographic keys, is limited in transmission distance. The development of a quantum repeater is a possible path to extend QKD range, but a repeater will need a quantum memory. In our experiments we use a gas of rubidium 87 vapor that is contained in a warm gas cell. This makes the scheme particularly simple. It is also a highly versatile scheme that enables in-memory refinement of the stored state, such as frequency shifting and bandwidth manipulation. The basis of the GEM protocol is to absorb the light into an ensemble of atoms that has been prepared in a magnetic field gradient. The reversal of this gradient leads to rephasing of the atomic polarization and thus recall of the stored optical state. We will outline how we prepare the atoms and this gradient and also describe some of the pitfalls that need to be avoided, in particular four-wave mixing, which can give rise to optical gain.

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Precision spectral manipulation: A demonstration using a coherent optical memory

Cited by 3 publications

References 6 publications

Quantum Nonlinear Optics Using Optical Memory

Quantum Nonlinear Optics Using Optical Memory

Dynamical observations of self-stabilizing stationary light

Gradient Echo Quantum Memory in Warm Atomic Vapor

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