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We implement a low-noise, broadband quantum memory for light via off-resonant two-photon absorption in warm atomic vapour. We store heralded single photons and verify that the retrieved fields are anti-bunched.
Airborne ultrawideband radars operating at VHF/UHF frequencies can be used to sound and image polar ice sheets with fine-resolution. The sensitivity of the radar depends upon the power-aperture product. High peak power coupled with a large aperture is required to sound more than 4-km thick ice. In this paper, we present the design of a 400-W power amplifier for operation over the frequency range of...
For memory applications and optical control of qubits ultrafast manipulation and high coupling efficiencies are desirable. Ultrafast coherent control can be achieved by the off-resonant Raman scheme [1]. There exist several colour centres with an optically accessible lambda-type energy structure which offer a level splitting large enough for broadband laser pulses.
A quantum optical memory (QM) is a device that can store and release quantum states of light on demand. Such a device is capable of synchronising probabilistic events, for example, locally synchronising non-deterministic photon sources for the generation of multi-photon states, or successful quantum gate operations within a quantum computational architecture [1], as well as for globally synchronising...
Quantum memories enable the synchronisation of photonic operations. Raman memories are a promising platform, but are susceptible to four-wave mixing noise. We present a demonstration of a cavity-enhanced Raman memory, showing suppression of four-wave mixing.
Summary Studies on juvenile individuals under artificial environments dominate knowledge about the sensitivity of trees to O3. Field approaches based on free-air O3 fumigations of adult forest trees are a novel choice. Such a case study on beech and spruce (at the Kranzberg Forest near Munich, Germany) is used to address four long-standing issues in O3 research: (1) Can a “unifying theory” of O3 sensitivity...
We demonstrate storage of heralded single photons in a room-temperature quantum memory, a key step towards scalable quantum networks. We evaluate the photon statistics of the stored photons and discuss limitations from four-wave mixing noise.
We address an optical quantum memory with multiple pulses, enabling unit efficiency readout and programmable beam splitting. The resulting coherent processor with built-in storage is universal for scalable photonic quantum information processing.
We demonstrate entanglement between the vibrational mode of two macroscopic, spatially-separated diamonds at room temperature with ultrashort pulses and a far-off-resonant Raman interaction.
Quantum memories capable of storing single photons are essential building blocks for quantum information processing, enabling the storage and transfer of quantum information over long distances [1]. Devices operating at room temperature can be deployed on a large scale and integrated into existing photonic networks, but so far warm quantum memories have been susceptible to noise at the single photon...
We present an efficient broadband optical single-photon-level room-temperature memory, capable of operating with a low unconditional noise floor in the quantum regime, with memory efficiencies exceeding 30% and storage times of up to 4 μs.
We demonstrate the coherent storage and retrieval of sub-nanosecond low-intensity light pulses with spectral bandwidths exceeding 1 GHz in cesium vapor, using the novel, far off-resonant two-photon Raman memory protocol.
Given an experimental set-up and a fixed number of measurements, how should one take data in order to optimally reconstruct the state of a quantum system? We show how to calculate the optimal design explicitly.
Quantum storage of multiple optical modes affords improved performance for quantum repeaters. We present new analytic and numerical results unifying the scaling of the multimode storage capacity for various memory protocols in artificially broadened ensembles.
Quantum storage of multiple optical modes affords improved performance for quantum repeaters. We present new analytic and numerical results unifying the scaling of the multimode storage capacity for various memory protocols in artificially broadened ensembles.
Summary form only given. The authors present a theoretical analysis of a quantum memory which shows how to efficiently transfer an ultrashort single photon wavepacket to a long-lived collective excitation of an ensemble of absorbers with the well-known three level Lambda-structure, by application of an ancillary control field. We describe a general prescription for optimizing the efficiency of the...
In this paper, we measure the decoherence time of phonons using spectral interference of the Stokes emission of diamond. Two 100 femtosecond laser pulses, separated by a delay tau, are sent through a polished diamond sample of 1.2 mm thickness. Optical phonons in the Brillouin zone centre are created by Raman scattering from the ultrafast laser pulses and can be heralded by the Stokes photons emitted,...
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