Continuous retrieval of delayed Raman polaritons (original) (raw)
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Continuous generation of delayed light
Journal of Physics B: Atomic, Molecular and Optical Physics
We use a Raman four-wave mixing process to read-out light from atomic coherence which is continuously written. The light is continuously generated after an effective delay, allowing the atomic coherence to evolve during the process. Contrary to slow-light delay, which depends on the medium optical depth, here the generation delay is determined solely by the intensive properties of the system, approaching the atomic coherence lifetime at the weak driving limit. The generated light is background free. We experimentally probe these properties utilizing spatial diffusion as an 'internal clock' for the atomic evolution time. Continuous generation of light with a long intrinsic delay can replace discrete write-read procedures when the atomic evolution is the subject of interest.
Storage of Light' in a Fast-Light Atomic Medium
Slow and Fast Light, 2006
Storage of light pulses in Rb vapour with bright Zeeman coherences and the associated enhanced absorption and steep negative dispersion is reported. Our experimental observations are qualitatively similar to the well-known proofof-principle demonstration of light storage (D F Phillips et al 2001 Phys. Rev. Lett. 86 783), but obtained under conditions where electromagnetically induced transparency (EIT) does not exist and the slow-light dark-state polariton model does not apply. Under the present experimental conditions the retrieved pulses obtained in atomic media with dark or bright Zeeman coherences have very similar exponentially decaying slopes which are independent of the shape of the incoming signal pulse. Numerical modelling based on the optical Bloch equations reproduces the essential features of the experimental observations.
Optical quantum memory with generalized time-reversible atom–light interaction
New Journal of Physics, 2011
We examine a quantum memory scheme based on controllable dephasing of atomic coherence of a non-resonant, inhomogeneously broadened Raman transition. We show that it generalizes the physical conditions for time-reversible interaction between light and atomic ensembles from weak to strong fields and from linear to non-linear interactions. We also develop a unified framework for different realizations exploiting either controlled reversible inhomogeneous broadening or atomic frequency combs, and discuss new aspects related to storage and manipulation of quantum states.
‘Storage of light’ in an atomic medium using electromagnetically induced absorption
Journal of Physics B: Atomic, Molecular and Optical Physics, 2005
Storage of light pulses in Rb vapour with bright Zeeman coherences and the associated enhanced absorption and steep negative dispersion is reported. Our experimental observations are qualitatively similar to the well-known proofof-principle demonstration of light storage (D F Phillips et al 2001 Phys. Rev. Lett. 86 783), but obtained under conditions where electromagnetically induced transparency (EIT) does not exist and the slow-light dark-state polariton model does not apply. Under the present experimental conditions the retrieved pulses obtained in atomic media with dark or bright Zeeman coherences have very similar exponentially decaying slopes which are independent of the shape of the incoming signal pulse. Numerical modelling based on the optical Bloch equations reproduces the essential features of experimental observations.
Quantum memory for photons: Dark-state polaritons
Physical Review A, 2002
An ideal and reversible transfer technique for the quantum state between light and metastable collective states of matter is presented and analyzed in detail. The method is based on the control of photon propagation in coherently driven three-level atomic media, in which the group velocity is adiabatically reduced to zero. Form-stable coupled excitations of light and matter ͑''dark-state polaritons''͒ associated with the propagation of quantum fields in electromagnetically induced transparency are identified, their basic properties discussed and their application for quantum memories for light analyzed.
Raman-assisted polarization beats in time-delayed four-wave mixing
Optics Letters, 1992
We demonstrate a method for determining the phase of the third-order susceptibility, 'y) in the proximity of a Raman resonance. The measurements were based on the phenomenon of polarization beats, which was exploited in a time-delayed four-wave-mixing experiment with bichromatic beams. The phase dispersion of X(3) was studied close to resonance with the 655.7-cm-1 vibrational mode of carbon disulfide.
Giant increase of temporal coherence in optically trapped polariton condensate
Coherent bosonic ensembles offer the promise of harnessing quantum effects in photonic and quantum circuits. In the dynamic equilibrium regime, the application of polariton condensates is hindered by exciton-polariton scattering induced de-coherence in the presence of a dark exciton reservoir. By spatially separating the condensate from the reservoir, we drive the system into the weak interaction regime, where the ensemble coherence time exceeds the individual particle lifetime by nearly three orders of magnitude. The observed nanosecond coherence provides an upper limit for polariton self-interactions. In contrast to conventional photon lasers, we observe an increased contribution from the super-Poissonian component of the condensate to the overall particle number fluctuations. Coupled with the recent emergence of a quantum regime in polaritonics, coherence times extended to several nanoseconds favour the realization of quantum information protocols.
Physical Review A, 2010
We consider a quantum memory scheme based on the conversion of a signal pulse into a long-lived spin coherence via stimulated off-resonant Raman process. For a storing medium consisting of alkali atoms, we have calculated the Autler-Townes resonance structure created by a strong control field. By taking into account the upper hyperfine states of the D1 optical transition, we show important deviations from the predictions of the usual three-level Λ-scheme approximation and we demonstrate an enhancement of the process for particular detunings of the control. We estimate the memory efficiency one can obtain using this configuration.
Ultralong quantum optical data storage using an optical locking technique
Nature Photonics, 2009
Several types of quantum memory protocols have been presented over the last ten years, including photon echoes 1-4 , off-resonant Raman scattering 5,6 , ultraslow light-based quantum mapping processes 7-10 and resonant Raman optical echoes 11 . These quantum optical memory protocols are limited by a storage time on a scale as short as milliseconds, determined by the spin phase decay time of the storage medium. For applications of long-distance quantum communications, a quantum repeater composed of quantum entanglement swapping and quantum memory must be used . Achieving longer storage times in quantum memory therefore brings a definite advantage to applications of quantum repeaters for long-distance quantum communications. Here, we propose a quantum optical data storage protocol to extend the storage time by several orders of magnitude beyond the conventional limitation of the order of milliseconds. The present ultralong quantum optical storage technique is achieved by introducing an optical locking method to the resonant Raman optical echo protocol 11 .