201
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Hétet G, Longdell JJ, Alexander AL, Lam PK, Sellars MJ. Electro-optic quantum memory for light using two-level atoms. PHYSICAL REVIEW LETTERS 2008; 100:023601. [PMID: 18232866 DOI: 10.1103/physrevlett.100.023601] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2007] [Indexed: 05/25/2023]
Abstract
We present a simple quantum memory scheme that allows for the storage of a light field in an ensemble of two-level atoms. The technique is analogous to the NMR gradient echo for which the imprinting and recalling of the input field are performed by controlling a linearly varying broadening. Our protocol is perfectly efficient in the limit of high optical depths and the output pulse is emitted in the forward direction. We provide a numerical analysis of the protocol together with an experiment performed in a solid state system. In close agreement with our model, the experiment shows a total efficiency of up to 15%, and a recall efficiency of 26%. We suggest simple realizable improvements for the experiment to surpass the no-cloning limit.
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Affiliation(s)
- G Hétet
- ARC COE for Quantum-Atom Optics, Australian National University, Canberra, ACT 0200, Australia
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202
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Zhu Z, Gauthier DJ, Boyd RW. Stored light in an optical fiber via stimulated Brillouin scattering. Science 2007; 318:1748-50. [PMID: 18079395 DOI: 10.1126/science.1149066] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
We describe a method for storing sequences of optical data pulses by converting them into long-lived acoustic excitations in an optical fiber through the process of stimulated Brillouin scattering. These stored pulses can be retrieved later, after a time interval limited by the lifetime of the acoustic excitation. In the experiment reported here, smooth 2-nanosecond-long pulses are stored for up to 12 nanoseconds with good readout efficiency: 29% at 4-nanosecond storage time and 2% at 12 nanoseconds. This method thus can potentially store data packets that are many bits long. It can be implemented at any wavelength where the fiber is transparent and can be incorporated into existing telecommunication networks because it operates using only commercially available components at room temperature.
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Affiliation(s)
- Zhaoming Zhu
- Duke University, Department of Physics, Box 90305, Durham, NC 27708, USA
- The Institute of Optics, University of Rochester, Rochester, NY 14627, USA
| | - Daniel J. Gauthier
- Duke University, Department of Physics, Box 90305, Durham, NC 27708, USA
- The Institute of Optics, University of Rochester, Rochester, NY 14627, USA
| | - Robert W. Boyd
- Duke University, Department of Physics, Box 90305, Durham, NC 27708, USA
- The Institute of Optics, University of Rochester, Rochester, NY 14627, USA
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203
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Bravo-Abad J, Soljacić M. Photonics: photonic crystals go dynamic. NATURE MATERIALS 2007; 6:799-800. [PMID: 17972929 DOI: 10.1038/nmat2036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
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204
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Novikova I, Phillips DF, Walsworth RL. Slow light with integrated gain and large pulse delay. PHYSICAL REVIEW LETTERS 2007; 99:173604. [PMID: 17995332 DOI: 10.1103/physrevlett.99.173604] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2007] [Indexed: 05/25/2023]
Abstract
We demonstrate slow and stored light in Rb vapor with a combination of desirable features: minimal loss and distortion of the pulse shape, and large fractional delay (>10). This behavior is enabled by (i) a group index that can be controllably varied during light pulse propagation, and (ii) controllable gain integrated into the medium to compensate for pulse loss. Any medium with the above two characteristics should be able to realize similarly high-performance slow light.
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Affiliation(s)
- Irina Novikova
- Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, USA
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205
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Akamatsu D, Yokoi Y, Arikawa M, Nagatsuka S, Tanimura T, Furusawa A, Kozuma M. Ultraslow propagation of squeezed vacuum pulses with electromagnetically induced transparency. PHYSICAL REVIEW LETTERS 2007; 99:153602. [PMID: 17995164 DOI: 10.1103/physrevlett.99.153602] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2006] [Revised: 07/16/2007] [Indexed: 05/25/2023]
Abstract
We have succeeded in observing ultraslow propagation of squeezed vacuum pulses with electromagnetically induced transparency. Squeezed vacuum pulses (probe lights) were incident on a laser-cooled 87Rb gas together with an intense coherent light (control light). A homodyne method sensitive to the vacuum state was employed for detecting the probe pulse passing through the gas. A delay of 3.1 micros was observed for the probe pulse having a temporal width of 10 micros.
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Affiliation(s)
- Daisuke Akamatsu
- Department of Physics, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8550, Japan
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206
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Lin ZF, Chui ST. Manipulating electromagnetic radiation with magnetic photonic crystals. OPTICS LETTERS 2007; 32:2288-90. [PMID: 17700761 DOI: 10.1364/ol.32.002288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
We examine manipulating electromagnetic waves in magnetic photonic crystals (MPCs) with external magnetic fields. We predict new giant magnetoreflectivity and giant magnetorefractivity effects: with an external magnetic field of a magnitude much smaller than the anisotropy field of the ferromagnet, the MPC can be changed from completely reflecting to nonreflecting with corresponding changes in the angle of refraction. Application to the storage of electromagnetic radiation is also discussed.
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Affiliation(s)
- Z F Lin
- Surface Physics Laboratory and Department of Physics, Fudan University, Shanghai 200433, China
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207
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Unks BE, Proite NA, Yavuz DD. Generation of high-power laser light with Gigahertz splitting. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2007; 78:083108. [PMID: 17764314 DOI: 10.1063/1.2776971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
We demonstrate the generation of two high-power laser beams whose frequencies are separated by the ground state hyperfine transition frequency in (87)Rb. The system uses a single master diode laser appropriately shifted by high frequency acousto-optic modulators and amplified by semiconductor tapered amplifiers. This produces two 1 W laser beams with a frequency spacing of 6.834 GHz and a relative frequency stability of 1 Hz. We discuss possible applications of this apparatus, including electromagnetically induced transparency-like effects and ultrafast qubit rotations.
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Affiliation(s)
- B E Unks
- Department of Physics, University of Wisconsin-Madison, Madison, WI 53706, USA
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208
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Buth C, Santra R, Young L. Electromagnetically induced transparency for x rays. PHYSICAL REVIEW LETTERS 2007; 98:253001. [PMID: 17678019 DOI: 10.1103/physrevlett.98.253001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2007] [Indexed: 05/16/2023]
Abstract
Electromagnetically induced transparency is predicted for x rays in laser-dressed neon gas. The x-ray photoabsorption cross section and polarizability near the Ne K edge are calculated using an ab initio theory suitable for optical strong-field problems. The laser wavelength is tuned close to the transition between 1s(-1)3s and 1s(-1)3p approximately 800 nm). The minimum laser intensity required to observe electromagnetically induced transparency is of the order of 10(12) W/cm(2). The ab initio results are discussed in terms of an exactly solvable three-level model. This work opens new opportunities for research with ultrafast x-ray sources.
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Affiliation(s)
- Christian Buth
- Argonne National Laboratory, Argonne, Illinois 60439, USA
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209
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Novikova I, Gorshkov AV, Phillips DF, Sørensen AS, Lukin MD, Walsworth RL. Optimal control of light pulse storage and retrieval. PHYSICAL REVIEW LETTERS 2007; 98:243602. [PMID: 17677964 DOI: 10.1103/physrevlett.98.243602] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2007] [Indexed: 05/16/2023]
Abstract
We demonstrate experimentally a procedure to obtain the maximum efficiency for the storage and retrieval of light pulses in atomic media. The procedure uses time-reversal to obtain optimal input signal pulse shapes. Experimental results in warm Rb vapor are in good agreement with theoretical predictions and demonstrate a substantial improvement of efficiency. This optimization procedure is applicable to a wide range of systems.
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Affiliation(s)
- Irina Novikova
- Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, USA
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210
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Totsuka K, Kobayashi N, Tomita M. Slow light in coupled-resonator-induced transparency. PHYSICAL REVIEW LETTERS 2007; 98:213904. [PMID: 17677774 DOI: 10.1103/physrevlett.98.213904] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2007] [Indexed: 05/16/2023]
Abstract
We performed optical pulse propagation experiments in a system in which two ultrahigh-Q silica microspheres of different diameters were coupled in tandem to a fiber taper to yield coupled-resonator-induced transparency. Nearly Gaussian-shaped optical pulses propagated with a large positive delay of 8.5 ns through a transparent frequency window, without significant attenuation, amplification, or pulse deformation, demonstrating classical analogy of the extremely slow light obtained with electromagnetically induced transparency.
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Affiliation(s)
- Kouki Totsuka
- Department of Physics, Faculty of Science, Shizuoka University, 836 Ohya, Shizuoka, 422-8529 Japan
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211
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Pugatch R, Shuker M, Firstenberg O, Ron A, Davidson N. Topological stability of stored optical vortices. PHYSICAL REVIEW LETTERS 2007; 98:203601. [PMID: 17677696 DOI: 10.1103/physrevlett.98.203601] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2007] [Indexed: 05/16/2023]
Abstract
We report an experiment in which an optical vortex is stored in a vapor of Rb atoms. Because of its 2pi phase twist, this mode, also known as the Laguerre-Gauss mode, is topologically stable and cannot unwind even under conditions of strong diffusion. For comparison, we stored a Gaussian beam with a dark center and a uniform phase. Contrary to the optical vortex, which stays stable for over 100 micros, the dark center in the retrieved flat-phased image was filled with light after a storage time as short as 10 micros. The experiment proves that higher electromagnetic modes can be converted into atomic coherences and that modes with phase singularities are robust to decoherence effects such as diffusion. This opens the possibility to more elaborate schemes for classical and quantum information storage in atomic vapors.
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Affiliation(s)
- R Pugatch
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel
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212
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Tarhan D, Postacioglu N, Müstecaplioglu OE. Ultraslow optical waveguiding in an atomic Bose-Einstein condensate. OPTICS LETTERS 2007; 32:1038-40. [PMID: 17410227 DOI: 10.1364/ol.32.001038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
We investigate waveguiding of ultraslow light pulses in an atomic Bose-Einstein condensate. We show that under the conditions of off-resonant electromagnetically induced transparency, waveguiding with a few ultraslow modes can be realized. The number of modes that can be supported by the condensate can be controlled by means of experimentally accessible parameters. Propagation constants and the mode conditions are determined analytically using a Wentzel-Kramers-Brillouin analysis. Mode profiles are found numerically.
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Affiliation(s)
- Devrim Tarhan
- Department of Physics, Istanbul Technical University, Istanbul, Turkey.
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213
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Camacho RM, Pack MV, Howell JC, Schweinsberg A, Boyd RW. Wide-bandwidth, tunable, multiple-pulse-width optical delays using slow light in cesium vapor. PHYSICAL REVIEW LETTERS 2007; 98:153601. [PMID: 17501346 DOI: 10.1103/physrevlett.98.153601] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2006] [Indexed: 05/13/2023]
Abstract
We demonstrate an all-optical delay line in hot cesium vapor that tunably delays 275 ps input pulses up to 6.8 ns and 740 input ps pulses up to 59 ns (group index of approximately 200) with little pulse distortion. The delay is made tunable with a fast reconfiguration time (hundreds of ns) by optically pumping out of the atomic ground states.
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Affiliation(s)
- Ryan M Camacho
- Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, USA
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214
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Wolf MM, Pérez-García D, Giedke G. Quantum capacities of bosonic channels. PHYSICAL REVIEW LETTERS 2007; 98:130501. [PMID: 17501173 DOI: 10.1103/physrevlett.98.130501] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2006] [Indexed: 05/15/2023]
Abstract
We investigate the capacity of bosonic quantum channels for the transmission of quantum information. We calculate the quantum capacity for a class of Gaussian channels, including channels describing optical fibers with photon losses, by proving that Gaussian encodings are optimal. For arbitrary channels we show that achievable rates can be determined from few measurable parameters by proving that every channel can asymptotically simulate a Gaussian channel which is characterized by second moments of the initial channel. Along the way we provide a complete characterization of degradable Gaussian channels and those arising from teleportation protocols.
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Affiliation(s)
- Michael M Wolf
- Max-Planck-Institute for Quantum Optics, Hans-Kopfermann-Strasse 1, D-85748 Garching, Germany
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215
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Gorshkov AV, André A, Fleischhauer M, Sørensen AS, Lukin MD. Universal approach to optimal photon storage in atomic media. PHYSICAL REVIEW LETTERS 2007; 98:123601. [PMID: 17501121 DOI: 10.1103/physrevlett.98.123601] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2006] [Indexed: 05/15/2023]
Abstract
We present a universal physical picture for describing storage and retrieval of photon wave packets in a Lambda-type atomic medium. This physical picture encompasses a variety of different approaches to pulse storage ranging from adiabatic reduction of the photon group velocity and pulse-propagation control via off-resonant Raman fields to photon-echo-based techniques. Furthermore, we derive an optimal control strategy for storage and retrieval of a photon wave packet of any given shape. All these approaches, when optimized, yield identical maximum efficiencies, which only depend on the optical depth of the medium.
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Affiliation(s)
- Alexey V Gorshkov
- Physics Department, Harvard University, Cambridge, Massachusetts 02138, USA
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216
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Jiang KJ, Deng L, Payne MG. Observation of quantum destructive interference in inelastic two-wave mixing. PHYSICAL REVIEW LETTERS 2007; 98:083604. [PMID: 17359100 DOI: 10.1103/physrevlett.98.083604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2006] [Indexed: 05/14/2023]
Abstract
Using room-temperature 87Rb atoms we demonstrate a quantum destructive interference between two one-photon excitation pathways in an inelastic two-wave mixing scheme that corresponds to the "strong-storage and weak-retrieval" of an optical field. This destructive interference is fundamentally different from the usual electromagnetically induced transparency because it is critically dependent on the generation and propagation of a wave-mixing field. We also show that contrary to the common belief, the maximum atomic coherence in general does not lead to the maximum mixing-wave conversion efficiency.
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Affiliation(s)
- K J Jiang
- Electron & Optical Physics Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
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217
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Ginsberg NS, Garner SR, Hau LV. Coherent control of optical information with matter wave dynamics. Nature 2007; 445:623-6. [PMID: 17287804 DOI: 10.1038/nature05493] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2006] [Accepted: 11/24/2006] [Indexed: 11/09/2022]
Abstract
In recent years, significant progress has been achieved in manipulating matter with light, and light with matter. Resonant laser fields interacting with cold, dense atom clouds provide a particularly rich system. Such light fields interact strongly with the internal electrons of the atoms, and couple directly to external atomic motion through recoil momenta imparted when photons are absorbed and emitted. Ultraslow light propagation in Bose-Einstein condensates represents an extreme example of resonant light manipulation using cold atoms. Here we demonstrate that a slow light pulse can be stopped and stored in one Bose-Einstein condensate and subsequently revived from a totally different condensate, 160 mum away; information is transferred through conversion of the optical pulse into a travelling matter wave. In the presence of an optical coupling field, a probe laser pulse is first injected into one of the condensates where it is spatially compressed to a length much shorter than the coherent extent of the condensate. The coupling field is then turned off, leaving the atoms in the first condensate in quantum superposition states that comprise a stationary component and a recoiling component in a different internal state. The amplitude and phase of the spatially localized light pulse are imprinted on the recoiling part of the wavefunction, which moves towards the second condensate. When this 'messenger' atom pulse is embedded in the second condensate, the system is re-illuminated with the coupling laser. The probe light is driven back on and the messenger pulse is coherently added to the matter field of the second condensate by way of slow-light-mediated atomic matter-wave amplification. The revived light pulse records the relative amplitude and phase between the recoiling atomic imprint and the revival condensate. Our results provide a dramatic demonstration of coherent optical information processing with matter wave dynamics. Such quantum control may find application in quantum information processing and wavefunction sculpting.
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Affiliation(s)
- Naomi S Ginsberg
- Department of Physics, and Division of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
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218
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219
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Camacho RM, Broadbent CJ, Ali-Khan I, Howell JC. All-optical delay of images using slow light. PHYSICAL REVIEW LETTERS 2007; 98:043902. [PMID: 17358768 DOI: 10.1103/physrevlett.98.043902] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2006] [Indexed: 05/14/2023]
Abstract
Two-dimensional images carried by optical pulses (2 ns) are delayed by up to 10 ns in a 10 cm cesium vapor cell. By interfering the delayed images with a local oscillator, the transverse phase and amplitude profiles of the images are shown to be preserved. It is further shown that delayed images can be well preserved even at very low light levels, where each pulse contains on average less than one photon.
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Affiliation(s)
- Ryan M Camacho
- Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, USA
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220
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Chen YF, Kuan PC, Wang SH, Wang CY, Yu IA. Manipulating the retrieved frequency and polarization of stored light pulses. OPTICS LETTERS 2006; 31:3511-3. [PMID: 17099767 DOI: 10.1364/ol.31.003511] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
We have experimentally demonstrated that stored and retrieved light pulses have different frequencies but maintain phase coherence; a stored light pulse is released with a different polarization. However, the manipulation process causes an energy loss of the retrieved pulse. We have discovered that Clebsch-Gordan coefficients among the Zeeman sublevels play an important role in the energy loss and have demonstrated a solution for avoiding the energy loss.
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Affiliation(s)
- Yong-Fan Chen
- Department of Physics, National Tsing Hua University, Hsinchu, Taiwan, China
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221
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Hsu MTL, Hétet G, Glöckl O, Longdell JJ, Buchler BC, Bachor HA, Lam PK. Quantum study of information delay in electromagnetically induced transparency. PHYSICAL REVIEW LETTERS 2006; 97:183601. [PMID: 17155542 DOI: 10.1103/physrevlett.97.183601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2006] [Indexed: 05/12/2023]
Abstract
Using electromagnetically induced transparency (EIT), it is possible to delay and store light in atomic ensembles. Theoretical modeling and recent experiments have suggested that the EIT storage mechanism can be used as a memory for quantum information. We present experiments that quantify the noise performance of an EIT system for conjugate amplitude and phase quadratures. It is shown that our EIT system adds excess noise to the delayed light that has not hitherto been predicted by published theoretical modeling. In analogy with other continuous-variable quantum information systems, the performance of our EIT system is characterized in terms of conditional variance and signal transfer.
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Affiliation(s)
- M T L Hsu
- ARC COE for Quantum-Atom Optics, Australian National University, Canberra, ACT 0200, Australia
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222
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Kohmoto T, Fukui Y, Furue S, Nakayama K, Fukuda Y. Propagation of femtosecond light pulses in a dye solution: nonadherence to the conventional group velocity. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 74:056603. [PMID: 17280002 DOI: 10.1103/physreve.74.056603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2006] [Indexed: 05/13/2023]
Abstract
Propagation of femtosecond light pulses in a resonant absorption medium is studied. The propagation time of the light pulses was measured in a dye solution by the optical-Kerr-gate method. Nonadherence to the conventional group velocity domega/dk , which is defined in weak absorption region, was found. The observed wavelength dependences of the group delay and the spectral change in the anomalous dispersion region are qualitatively in good agreement with the theoretical prediction obtained from the new definitions of group velocity, which can be clearly defined even in strong absorption region.
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Affiliation(s)
- T Kohmoto
- Department of Physics, Faculty of Science, Kobe University, Kobe 657-8501, Japan
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223
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224
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Figueroa E, Vewinger F, Appel J, Lvovsky AI. Decoherence of electromagnetically induced transparency in atomic vapor. OPTICS LETTERS 2006; 31:2625-7. [PMID: 16902640 DOI: 10.1364/ol.31.002625] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
We report characterization of electromagnetically induced transparency (EIT) resonances in the D1 line of (87)Rb under various experimental conditions. The dependence of the EIT linewidth on the power of the pump field was investigated at various temperatures for the ground states of the lambda system associated with different hyperfine levels of the atomic 5S(1/2) state as well as magnetic sublevels of the same hyperfine level. Strictly linear behavior was observed in all cases. A theoretical analysis of our results shows that dephasing in the ground state is the main source of decoherence, with population exchange playing a minor role.
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Affiliation(s)
- E Figueroa
- Institute of Quantum Information Science, University of Calgary, Alberta, Canada
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225
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He H, Hu Z, Wang Y, Wang L, Zhu S. Superluminal light propagation assisted by Zeeman coherence. OPTICS LETTERS 2006; 31:2486-8. [PMID: 16880864 DOI: 10.1364/ol.31.002486] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
We have observed a dispersionlike absorption (or gain) spectrum at the D1 transition in a Rb vapor cell filled with a buffer gas, due to Zeeman coherence of the ground states in a double Lambda configuration. Meanwhile, we have also observed superluminal pulse propagation. It is experimentally demonstrated that the front speed of a light pulse still equals the light speed c in vacuum, although the group velocity of the light pulse is(-2.2+/-0.6) x 10(4) m/s.
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Affiliation(s)
- Huijuan He
- Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Science, Shanghai 201800, China
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226
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Wang CY, Chen YF, Lin SC, Lin WH, Kuan PC, Yu IA. Low-light-level all-optical switching. OPTICS LETTERS 2006; 31:2350-2. [PMID: 16832482 DOI: 10.1364/ol.31.002350] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
We propose an all-optical switch that utilizes the technique of storage and retrieval of light pulses. A single photon (probe pulse) switched by another (switching pulse) is feasible, and the on-off ratio can be as large as 10 dB. We have experimentally demonstrated that the energy of the retrieved probe pulse is reduced to about 10% because of the presence of a switching pulse with an energy per unit area of one photon per lambda(2)/(2pi). The achieved result does not depend on the coupling intensity, the atomic optical density, or the width and shape of the switching pulse.
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Affiliation(s)
- Chang-Yi Wang
- Department of Physics, National Hsing Hua University, Hsinchu, Taiwan 300, China
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227
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Ghosh S, Bhagwat AR, Renshaw CK, Goh S, Gaeta AL, Kirby BJ. Low-light-level optical interactions with rubidium vapor in a photonic band-gap fiber. PHYSICAL REVIEW LETTERS 2006; 97:023603. [PMID: 16907442 DOI: 10.1103/physrevlett.97.023603] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2006] [Indexed: 05/11/2023]
Abstract
We show that rubidium vapor can be produced within the core of a photonic band-gap fiber yielding an optical depth in excess of 2,000. Our technique for producing the vapor is based on coating the inner walls of the fiber core with organosilane and using light-induced atomic desorption to release Rb atoms into the core. As an initial demonstration of the potential of this system for supporting ultralow-level nonlinear optical interactions, we perform electromagnetically induced transparency with control-field powers in the nanowatt regime, which represents more than a 1,000-fold reduction from the power required for bulk, focused geometries.
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Affiliation(s)
- Saikat Ghosh
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
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228
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Agarwal GS. Interferences in parametric interactions driven by quantized fields. PHYSICAL REVIEW LETTERS 2006; 97:023601. [PMID: 16907440 DOI: 10.1103/physrevlett.97.023601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2006] [Indexed: 05/11/2023]
Abstract
We report interferences in the quantum fluctuations of the output of a parametric amplifier when the cavity is driven by a quantized field at the signal frequency. The interferences depend on the phase fluctuations of the input quantized field and result in splitting of the spectrum of the output, and thus the recent observation [H. Ma, Phys. Rev. Lett. 95, 233601 (2005)10.1103/PhysRevLett.95.233601] of interferences in the classical domain have a very interesting counterpart in the quantum domain. The interferences can be manipulated, for example, by changing the amount of squeezing in the input field.
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Affiliation(s)
- G S Agarwal
- Department of Physics, Oklahoma State University, Stillwater, 74078, USA
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229
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Thompson JK, Simon J, Loh H, Vuletic V. A High-Brightness Source of Narrowband, Identical-Photon Pairs. Science 2006; 313:74-7. [PMID: 16825564 DOI: 10.1126/science.1127676] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
We generated narrowband pairs of nearly identical photons at a rate of 5 x 10(4) pairs per second from a laser-cooled atomic ensemble inside an optical cavity. A two-photon interference experiment demonstrated that the photons could be made 90% indistinguishable, a key requirement for quantum information-processing protocols. Used as a conditional single-photon source, the system operated near the fundamental limits on recovery efficiency (57%), Fourier transform-limited bandwidth, and pair-generation-rate-limited suppression of two-photon events (factor of 33 below the Poisson limit). Each photon had a spectral width of 1.1 megahertz, ideal for interacting with atomic ensembles that form the basis of proposed quantum memories and logic.
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Affiliation(s)
- James K Thompson
- Department of Physics, MIT-Harvard Center for Ultracold Atoms, Research Laboratory of Electronics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
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230
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Huang G, Jiang K, Payne MG, Deng L. Formation and propagation of coupled ultraslow optical soliton pairs in a cold three-state double- system. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 73:056606. [PMID: 16803056 DOI: 10.1103/physreve.73.056606] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2006] [Indexed: 05/10/2023]
Abstract
We investigate the simultaneous formation and propagation of coupled ultraslow optical soliton pairs in a cold, lifetime-broadened three-state double-Lambda atomic system. Starting from the equations of motion of atomic response and two-mode probe-control electromagnetic fields, we derive coupled nonlinear Schrödinger equations that govern the nonlinear evolution of the envelopes of the probe fields in this four-wave mixing scheme by means of the standard method of multiple scales. We demonstrate that for weak probe fields and with suitable operation conditions, a pair of coupled optical solitons moving with remarkably slow propagating velocity can be established in such a highly resonant atomic medium. The key elements to such a shape preserving, well matched yet interacting soliton pair is the balance between dispersion effect and self- and cross-phase modulation effects of the system.
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Affiliation(s)
- Guoxiang Huang
- Department of Physics, East China Normal University, Shanghai, China.
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231
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Hang C, Huang G, Deng L. Generalized nonlinear Schrödinger equation and ultraslow optical solitons in a cold four-state atomic system. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 73:036607. [PMID: 16605677 DOI: 10.1103/physreve.73.036607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2005] [Indexed: 05/08/2023]
Abstract
We investigate the influence of high-order dispersion and nonlinearity on the propagation of ultraslow optical solitons in a lifetime broadened four-state atomic system under a Raman excitation. Using a standard method of multiple-scales we derive a generalized nonlinear Schrödinger equation and show that for realistic physical parameters and at the pulse duration of 10(-6)s, the effects of third-order linear dispersion, nonlinear dispersion, and delay in nonlinear refractive index can be significant and may not be considered as perturbations. We provide exact soliton solutions for the generalized nonlinear Schrödinger equation and demonstrate that optical solitons obtained may still have ultraslow propagating velocity. Numerical simulations on the stability and interaction of these ultraslow optical solitons in the presence of linear and differential absorptions are also presented.
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Affiliation(s)
- Chao Hang
- Department of Physics, East China Normal University, Shanghai 200062, China
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232
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Scheuer J, Yariv A. Sagnac effect in coupled-resonator slow-light waveguide structures. PHYSICAL REVIEW LETTERS 2006; 96:053901. [PMID: 16486930 DOI: 10.1103/physrevlett.96.053901] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2005] [Indexed: 05/06/2023]
Abstract
We study the effect of rotation on the propagation of electromagnetic waves in slow-light waveguide structures consisting of coupled microring resonators. We show that such configurations exhibit a new type of Sagnac effect which can be used for the realization of highly compact integrated rotation sensors and gyroscopes.
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Affiliation(s)
- Jacob Scheuer
- Center for the Physics of Information, California Institute of Technology, M/C 128-95, Pasadena, California 91125, USA.
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233
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Parkins AS, Solano E, Cirac JI. Unconditional two-mode squeezing of separated atomic ensembles. PHYSICAL REVIEW LETTERS 2006; 96:053602. [PMID: 16486929 DOI: 10.1103/physrevlett.96.053602] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2005] [Indexed: 05/06/2023]
Abstract
We propose schemes for the unconditional preparation of a two-mode squeezed state of effective bosonic modes realized in a pair of atomic ensembles interacting collectively with optical cavity and laser fields. The scheme uses Raman transitions between stable atomic ground states and under ideal conditions produces pure entangled states in the steady state. The scheme works both for ensembles confined within a single cavity and for ensembles confined in separate, cascaded cavities.
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Affiliation(s)
- A S Parkins
- Max-Planck Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching, Germany
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234
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Chen YF, Wang CY, Wang SH, Yu IA. Low-light-level cross-phase-modulation based on stored light pulses. PHYSICAL REVIEW LETTERS 2006; 96:043603. [PMID: 16486821 DOI: 10.1103/physrevlett.96.043603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2005] [Indexed: 05/06/2023]
Abstract
We experimentally demonstrate a low-light-level cross-phase-modulation (XPM) scheme based on the light-storage technique in laser-cooled 87Rb atoms. The proposed scheme can achieve a similar phase shift and has the same figure of merit as one using static electromagnetically induced transparency under the constant coupling field. Nevertheless, the phase shift and the energy loss of a probe pulse induced by a signal pulse are neither influenced by the coupling intensity nor by the atomic optical density in the light-storage XPM scheme. This scheme enhances the flexibility of the experiment and makes possible conditional phase shifts on the order of pi with single photons.
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Affiliation(s)
- Yong-Fan Chen
- Department of Physics, National Tsing Hua University, Hsinchu, Taiwan 300, Republic of China
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235
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Alexander AL, Longdell JJ, Sellars MJ, Manson NB. Photon echoes produced by switching electric fields. PHYSICAL REVIEW LETTERS 2006; 96:043602. [PMID: 16486820 DOI: 10.1103/physrevlett.96.043602] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2005] [Indexed: 05/06/2023]
Abstract
We demonstrate photon echoes in Eu3+:Y2SiO5 by controlling the inhomogeneous broadening of the Eu3+ 7F0<-->5D0 optical transition. This transition has a linear Stark shift, and we induce inhomogeneous broadening by applying an external electric field gradient. After optical excitation, reversing the polarity of the field rephases the ensemble, resulting in a photon echo. This is the first demonstration of such a photon echo, and its application as a quantum memory is discussed.
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Affiliation(s)
- A L Alexander
- Laser Physics Centre, Research School of Physical Sciences and Engineering, Australian National University, Canberra, ACT 0200, Australia
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236
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Matsukevich DN, Chanelière T, Jenkins SD, Lan SY, Kennedy TAB, Kuzmich A. Observation of dark state polariton collapses and revivals. PHYSICAL REVIEW LETTERS 2006; 96:033601. [PMID: 16486697 DOI: 10.1103/physrevlett.96.033601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2005] [Indexed: 05/06/2023]
Abstract
By time-dependent variation of a control field, both coherent and single-photon states of light are stored in, and retrieved from, a cold atomic gas. The efficiency of retrieval is studied as a function of the storage time in an applied magnetic field. A series of collapses and revivals is observed, in very good agreement with theoretical predictions. The observations are interpreted in terms of the time evolution of the collective excitation of atomic spin wave and light wave, known as the dark-state polariton.
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Affiliation(s)
- D N Matsukevich
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, USA
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237
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Matsukevich DN, Chanelière T, Jenkins SD, Lan SY, Kennedy TAB, Kuzmich A. Entanglement of remote atomic qubits. PHYSICAL REVIEW LETTERS 2006; 96:030405. [PMID: 16486672 DOI: 10.1103/physrevlett.96.030405] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2005] [Indexed: 05/06/2023]
Abstract
We report observations of entanglement of two remote atomic qubits, achieved by generating an entangled state of an atomic qubit and a single photon at site , transmitting the photon to site in an adjacent laboratory through an optical fiber, and converting the photon into an atomic qubit. Entanglement of the two remote atomic qubits is inferred by performing, locally, quantum state transfer of each of the atomic qubits onto a photonic qubit and subsequent measurement of polarization correlations in violation of the Bell inequality [EQUATION: SEE TEXT]. We experimentally determine [EQUATION: SEE TEXT]. Entanglement of two remote atomic qubits, each qubit consisting of two independent spin wave excitations, and reversible, coherent transfer of entanglement between matter and light represent important advances in quantum information science.
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Affiliation(s)
- D N Matsukevich
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, USA
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238
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Scully MO, Fry ES, Ooi CHR, Wódkiewicz K. Directed spontaneous emission from an extended ensemble of N atoms: timing is everything. PHYSICAL REVIEW LETTERS 2006; 96:010501. [PMID: 16486428 DOI: 10.1103/physrevlett.96.010501] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2005] [Indexed: 05/06/2023]
Abstract
A collection of static atoms is fixed in a crystal at a low temperature and prepared by a pulse of incident radiation of wave vector . The atoms are well described by an entangled Dicke-like state, in which each atom carries a characteristic phase factor exp(ik0.r(j)), where is the atomic position in the crystal. It is shown that a single photon absorbed by the N atoms will be followed by spontaneous emission in the same direction. Furthermore, phase matched emission is found when one photon is absorbed by N atoms followed by two-photon down-conversion.
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Affiliation(s)
- Marlan O Scully
- Max-Planck-Institut für Quantenoptik, D-85748, Garching, Germany
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239
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Barceló C, Liberati S, Visser M. Analogue Gravity. LIVING REVIEWS IN RELATIVITY 2005; 8:12. [PMID: 28179871 PMCID: PMC5255570 DOI: 10.12942/lrr-2005-12] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/07/2005] [Indexed: 05/13/2023]
Abstract
Analogue models of (and for) gravity have a long and distinguished history dating back to the earliest years of general relativity. In this review article we will discuss the history, aims, results, and future prospects for the various analogue models. We start the discussion by presenting a particularly simple example of an analogue model, before exploring the rich history and complex tapestry of models discussed in the literature. The last decade in particular has seen a remarkable and sustained development of analogue gravity ideas, leading to some hundreds of published articles, a workshop, two books, and this review article. Future prospects for the analogue gravity programme also look promising, both on the experimental front (where technology is rapidly advancing) and on the theoretical front (where variants of analogue models can be used as a springboard for radical attacks on the problem of quantum gravity).
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Affiliation(s)
- Carlos Barceló
- Instituto de Astrofísica de Andalucía (CSIC), Camino Bajo de Huetor 50, 18008 Granada, Spain
| | - Stefano Liberati
- International School for Advanced Studies and INFN, Via Beirut 2-4, 34014 Trieste, Italy
| | - Matt Visser
- School of Mathematics, Statistics, and Computer Science, Victoria University of Wellington, PO Box 600, Wellington, New Zealand
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240
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Friedler I, Kurizki G, Cohen O, Segev M. Spatial Thirring-type solitons via electromagnetically induced transparency. OPTICS LETTERS 2005; 30:3374-6. [PMID: 16389836 DOI: 10.1364/ol.30.003374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
We show that the giant Kerr nonlinearity in the regime of electromagnetically induced transparency in vapor can give rise to the formation of Thirring-type spatial solitons, which are supported solely by cross-phase modulation that couples the two copropagating light beams.
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Affiliation(s)
- Inbal Friedler
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
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241
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Vengalattore M, Prentiss M. Radial confinement of light in an ultracold anisotropic medium. PHYSICAL REVIEW LETTERS 2005; 95:243601. [PMID: 16384376 DOI: 10.1103/physrevlett.95.243601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2005] [Indexed: 05/05/2023]
Abstract
We demonstrate radial confinement and waveguiding of light in an ultracold anisotropic gas. The waveguiding medium is a laser cooled ensemble of rubidium atoms confined in a trap of large aspect ratio. A recoil induced resonance (RIR) is used to create strong dispersion and large gain in this ensemble. The combination of the anisotropic trap and the RIR give rise to a spatially varying group refractive index resulting in a slow-light optical waveguide. Waveguided pulses of light experience strong gain (approximately 50), low group velocities (c approximately 1500 m/s), and long group delays (delta approximately 7 micros) due to the enhanced path length.
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Affiliation(s)
- Mukund Vengalattore
- Center for Ultracold Atoms, Jefferson Laboratory, Physics Department, Harvard University, Cambridge, Massachusetts 02138, USA.
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242
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Ma H, Ye C, Wei D, Zhang J. Coherence phenomena in the phase-sensitive optical parametric amplification inside a cavity. PHYSICAL REVIEW LETTERS 2005; 95:233601. [PMID: 16384306 DOI: 10.1103/physrevlett.95.233601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2005] [Indexed: 05/05/2023]
Abstract
We theoretically and experimentally demonstrate coherence phenomena in optical parametric amplification inside a cavity. The mode splitting in the transmission spectra of a phase-sensitive optical parametric amplifier is observed. Especially, we show that a very narrow dip and peak, which are the shape of a delta function, appear in the transmission profile. The origin of the coherence phenomenon in this system is the interference between the harmonic pump field and the subharmonic seed field in cooperation with dissipation of the cavity.
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Affiliation(s)
- Hongliang Ma
- The State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006, People's Republic of China
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243
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Eisaman MD, André A, Massou F, Fleischhauer M, Zibrov AS, Lukin MD. Electromagnetically induced transparency with tunable single-photon pulses. Nature 2005; 438:837-41. [PMID: 16341010 DOI: 10.1038/nature04327] [Citation(s) in RCA: 157] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2005] [Accepted: 10/13/2005] [Indexed: 11/09/2022]
Abstract
Techniques to facilitate controlled interactions between single photons and atoms are now being actively explored. These techniques are important for the practical realization of quantum networks, in which multiple memory nodes that utilize atoms for generation, storage and processing of quantum states are connected by single-photon transmission in optical fibres. One promising avenue for the realization of quantum networks involves the manipulation of quantum pulses of light in optically dense atomic ensembles using electromagnetically induced transparency (EIT, refs 8, 9). EIT is a coherent control technique that is widely used for controlling the propagation of classical, multi-photon light pulses in applications such as efficient nonlinear optics. Here we demonstrate the use of EIT for the controllable generation, transmission and storage of single photons with tunable frequency, timing and bandwidth. We study the interaction of single photons produced in a 'source' ensemble of 87Rb atoms at room temperature with another 'target' ensemble. This allows us to simultaneously probe the spectral and quantum statistical properties of narrow-bandwidth single-photon pulses, revealing that their quantum nature is preserved under EIT propagation and storage. We measure the time delay associated with the reduced group velocity of the single-photon pulses and report observations of their storage and retrieval.
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Affiliation(s)
- M D Eisaman
- Physics Department, Harvard University, Cambridge, Massachusetts 02138, USA
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244
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Chanelière T, Matsukevich DN, Jenkins SD, Lan SY, Kennedy TAB, Kuzmich A. Storage and retrieval of single photons transmitted between remote quantum memories. Nature 2005; 438:833-6. [PMID: 16341009 DOI: 10.1038/nature04315] [Citation(s) in RCA: 168] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2005] [Accepted: 10/13/2005] [Indexed: 11/09/2022]
Abstract
An elementary quantum network operation involves storing a qubit state in an atomic quantum memory node, and then retrieving and transporting the information through a single photon excitation to a remote quantum memory node for further storage or analysis. Implementations of quantum network operations are thus conditioned on the ability to realize matter-to-light and/or light-to-matter quantum state mappings. Here we report the generation, transmission, storage and retrieval of single quanta using two remote atomic ensembles. A single photon is generated from a cold atomic ensemble at one site , and is directed to another site through 100 metres of optical fibre. The photon is then converted into a single collective atomic excitation using a dark-state polariton approach. After a programmable storage time, the atomic excitation is converted back into a single photon. This is demonstrated experimentally, for a storage time of 0.5 microseconds, by measurement of an anti-correlation parameter. Storage times exceeding ten microseconds are observed by intensity cross-correlation measurements. This storage period is two orders of magnitude longer than the time required to achieve conversion between photonic and atomic quanta. The controlled transfer of single quanta between remote quantum memories constitutes an important step towards distributed quantum networks.
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Affiliation(s)
- T Chanelière
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
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245
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Chen YF, Tsai ZH, Liu YC, Yu IA. Low-light-level photon switching by quantum interference. OPTICS LETTERS 2005; 30:3207-9. [PMID: 16342722 DOI: 10.1364/ol.30.003207] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
We report an experimental demonstration of low-light-level photon switching by quantum interference in laser-cooled 87Rb atoms. A resonant probe pulse with an energy per unit area of one photon per lambda2/2pi propagates through the optically thick atoms. Its energy transmittance is greater than 63%, or a loss of less than e(-1), because of the effect of electromagnetically induced transparency. In the presence of a switching pulse with an energy per unit area of 1.4 photons per lambda2/2pi, the energy transmittance of the same probe pulse becomes less than 37%, or e(-1). This substantial reduction of probe transmittance caused by switching photons may lead to potential applications in single-photon-level nonlinear optics and manipulation of quantum information.
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Affiliation(s)
- Yong-Fan Chen
- Department of Physics, National Tsing Hua University, Hsinchu, Taiwan
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246
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Carter SG, Birkedal V, Wang CS, Coldren LA, Maslov AV, Citrin DS, Sherwin MS. Quantum Coherence in an Optical Modulator. Science 2005; 310:651-3. [PMID: 16254182 DOI: 10.1126/science.1116195] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Semiconductor quantum well electroabsorption modulators are widely used to modulate near-infrared (NIR) radiation at frequencies below 0.1 terahertz (THz). Here, the NIR absorption of undoped quantum wells was modulated by strong electric fields with frequencies between 1.5 and 3.9 THz. The THz field coupled two excited states (excitons) of the quantum wells, as manifested by a new THz frequency- and power-dependent NIR absorption line. Nonperturbative theory and experiment indicate that the THz field generated a coherent quantum superposition of an absorbing and a nonabsorbing exciton. This quantum coherence may yield new applications for quantum well modulators in optical communications.
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Affiliation(s)
- S G Carter
- Physics Department and Institute for Quantum and Complex Dynamics (iQCD), Broida Hall Building 572, Room 3410, University of California, Santa Barbara, CA 93106, USA
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247
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Fu KMC, Santori C, Stanley C, Holland MC, Yamamoto Y. Coherent population trapping of electron spins in a high-purity n-type GaAs semiconductor. PHYSICAL REVIEW LETTERS 2005; 95:187405. [PMID: 16383948 DOI: 10.1103/physrevlett.95.187405] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2005] [Indexed: 05/05/2023]
Abstract
In high-purity n-type GaAs under a strong magnetic field, we are able to isolate a lambda system composed of two Zeeman states of neutral-donor-bound electrons and the lowest Zeeman state of bound excitons. When the two-photon detuning of this system is zero, we observe a pronounced dip in the excited-state photoluminescence, indicating the creation of the coherent population-trapped state. Our data are consistent with a steady-state three-level density-matrix model. The observation of coherent population trapping in GaAs indicates that this and similar semiconductor systems could be used for various electromagnetically induced transparency type experiments.
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Affiliation(s)
- Kai-Mei C Fu
- Quantum Entanglement Project, ICORP, JST, Edward L. Ginzton Laboratory, Stanford University, California 94305-4085, USA.
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248
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Pestov D, Zhi M, Sariyanni ZE, Kalugin NG, Kolomenskii AA, Murawski R, Paulus GG, Sautenkov VA, Schuessler H, Sokolov AV, Welch GR, Rostovtsev YV, Siebert T, Akimov DA, Graefe S, Kiefer W, Scully MO. Visible and UV coherent Raman spectroscopy of dipicolinic acid. Proc Natl Acad Sci U S A 2005; 102:14976-81. [PMID: 16217021 PMCID: PMC1257716 DOI: 10.1073/pnas.0506529102] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We use time-resolved coherent Raman spectroscopy to obtain molecule-specific signals from dipicolinic acid (DPA), which is a marker molecule for bacterial spores. We use femtosecond laser pulses in both visible and UV spectral regions and compare experimental results with theoretical predictions. By exciting vibrational coherence on more than one mode simultaneously, we observe a quantum beat signal that can be used to extract the parameters of molecular motion in DPA. The signal is enhanced when an UV probe pulse is used, because its frequency is near-resonant to the first excited electronic state of the molecule. The capability for unambiguous identification of DPA molecules will lead to a technique for real-time detection of spores.
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Affiliation(s)
- Dmitry Pestov
- Institute for Quantum Studies, Texas A&M University, College Station, TX 77843-4242, USA
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249
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Yang Q, Seo JT, Tabibi B, Wang H. Slow light and superluminality in Kerr media without a pump. PHYSICAL REVIEW LETTERS 2005; 95:063902. [PMID: 16090955 DOI: 10.1103/physrevlett.95.063902] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2004] [Indexed: 05/03/2023]
Abstract
Subluminal and superluminal propagation of a light pulse in Kerr materials has been investigated. Group velocities as slow as much less than 1 mm per second to as fast as negative several thousands meters per second can easily be obtained in the Kerr medium, which possesses a large nonlinear refractive index and long relaxation time, such as Cr3+-doped alexandrite, ruby, and GdAlO3. The physical mechanism is the strong highly dispersive coupling between different frequency components of the pulse.
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Affiliation(s)
- Qiguang Yang
- Department of Physics, Hampton University, Hampton, Virginia 23668, USA.
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250
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Longdell JJ, Fraval E, Sellars MJ, Manson NB. Stopped light with storage times greater than one second using electromagnetically induced transparency in a solid. PHYSICAL REVIEW LETTERS 2005; 95:063601. [PMID: 16090952 DOI: 10.1103/physrevlett.95.063601] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2005] [Indexed: 05/03/2023]
Abstract
We report on the demonstration of light storage for times greater than a second in praseodymium doped Y2SiO5 using electromagnetically induced transparency. The long storage times were enabled by the long coherence times possible for the hyperfine transitions in this material. The use of a solid-state system also enabled operation with the probe and coupling beam counter-propagating, allowing easy separation of the two beams. The efficiency of the storage was low because of the low optical thickness of the sample; as is discussed, this deficiency should be easy to rectify.
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Affiliation(s)
- J J Longdell
- Laser Physics Centre, Research School of Physical Sciences and Engineering, Australian National University, Canberra, ACT 0200, Australia.
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