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Alain Aspect - One of the best experts on this subject based on the ideXlab platform.

  • Quasicontinuous horizontally guided Atom Laser: coupling spectrum and flux limits
    New Journal of Physics, 2011
    Co-Authors: Alain Bernard, Juliette Billy, Vincent Josse, Alain Aspect, William Guerin, Fred Jendrzejewski, Patrick Cheinet, Philippe Bouyer
    Abstract:

    We study in detail the flux properties of a radiofrequency outcoupled horizontally guided Atom Laser, following the scheme demonstrated in [Guerin W et al. 2006 Phys. Rev. Lett. 97 200402]. Both the outcoupling spectrum (flux of the Atom Laser versus rf frequency of the outcoupler) and the flux limitations imposed to operate in the quasicontinuous regime are investigated. These aspects are studied using a quasi-1D model, whose predictions are shown to be in fair agreement with the experimental observations. This work allows us to identify the operating range of the guided Atom Laser and to confirm its good promises in view of studying quantum transport phenomena.

  • Theoretical tools for Atom-Laser-beam propagation
    Physical Review A, 2008
    Co-Authors: J.-f. Riou, Alain Aspect, William Guerin, Y. Le Coq, François Impens, Christian J. Bordé, Philippe Bouyer
    Abstract:

    We present a theoretical model for the propagation of non-self-interacting Atom Laser beams. We start from a general propagation integral equation and we use the same approximations as in photon optics to derive tools to calculate the Atom-Laser-beam propagation. We discuss the approximations that allow one to reduce the general equation whether to a Fresnel-Kirchhoff integral calculated by using the stationary phase method, or to the eikonal. Within the paraxial approximation, we also introduce the $ABCD$ matrices formalism and the beam quality factor. As an example, we apply these tools to analyze the recent experiment by Riou et al. [Phys. Rev. Lett. 96, 070404 (2006)].

  • Theoretical tools for Atom-Laser-beam propagation
    Physical Review A, 2008
    Co-Authors: J.-f. Riou, Alain Aspect, Y. Le Coq, William Guerin, François Impens, Christian Bordé, Philippe Bouyer
    Abstract:

    We present a theoretical model for the propagation of non-self-interacting Atom Laser beams. We start from a general propagation integral equation and we use the same approximations as in photon optics to derive tools to calculate the Atom-Laser-beam propagation. We discuss the approximations that allow one to reduce the general equation whether to a Fresnel-Kirchhoff integral calculated by using the stationary phase method, or to the eikonal. Within the paraxial approximation, we also introduce the ABCD matrices formalism and the beam quality factor. As an example, we apply these tools to analyze the recent experiment.

  • Guided Atom Laser : a new tool for guided Atom optics
    Annales de Physique, 2007
    Co-Authors: Juliette Billy, Z. Zuo, W Guerin, Vincent Josse, Alain Aspect, Philippe Bouyer
    Abstract:

    We present a guided Atom Laser. A Bose-Einstein condensate (BEC) is created in a crossed hybrid magnetic and an elongated optical trap, which acts as a matterwave guide. Atoms are extracted from the BEC by radio frequency (rf) outcoupling and then guided in the horizontal optical matterwave guide. This method allows to control the acceleration of the beam and to achieve large de Broglie wavelength. We also measure the longitudinal energy of the guided Atom Laser using Atom optical elements based on a blue light barrier.

  • guided quasicontinuous Atom Laser
    Physical Review Letters, 2006
    Co-Authors: William Guerin, Vincent Josse, Philippe Bouyer, J.-f. Riou, John Gaebler, Alain Aspect
    Abstract:

    We report the first realization of a guided quasicontinuous Atom Laser by rf outcoupling a Bose-Einstein condensate from a hybrid optomagnetic trap into a horizontal Atomic waveguide. This configuration allows us to cancel the acceleration due to gravity and keep the de Broglie wavelength constant at $0.5\text{ }\text{ }\ensuremath{\mu}\mathrm{m}$ during 0.1 s of propagation. We also show that our configuration, equivalent to pigtailing an optical fiber to a (photon) semiconductor Laser, ensures an intrinsically good transverse mode matching.

Philippe Bouyer - One of the best experts on this subject based on the ideXlab platform.

  • Quasicontinuous horizontally guided Atom Laser: coupling spectrum and flux limits
    New Journal of Physics, 2011
    Co-Authors: Alain Bernard, Juliette Billy, Vincent Josse, Alain Aspect, William Guerin, Fred Jendrzejewski, Patrick Cheinet, Philippe Bouyer
    Abstract:

    We study in detail the flux properties of a radiofrequency outcoupled horizontally guided Atom Laser, following the scheme demonstrated in [Guerin W et al. 2006 Phys. Rev. Lett. 97 200402]. Both the outcoupling spectrum (flux of the Atom Laser versus rf frequency of the outcoupler) and the flux limitations imposed to operate in the quasicontinuous regime are investigated. These aspects are studied using a quasi-1D model, whose predictions are shown to be in fair agreement with the experimental observations. This work allows us to identify the operating range of the guided Atom Laser and to confirm its good promises in view of studying quantum transport phenomena.

  • Theoretical tools for Atom-Laser-beam propagation
    Physical Review A, 2008
    Co-Authors: J.-f. Riou, Alain Aspect, William Guerin, Y. Le Coq, François Impens, Christian J. Bordé, Philippe Bouyer
    Abstract:

    We present a theoretical model for the propagation of non-self-interacting Atom Laser beams. We start from a general propagation integral equation and we use the same approximations as in photon optics to derive tools to calculate the Atom-Laser-beam propagation. We discuss the approximations that allow one to reduce the general equation whether to a Fresnel-Kirchhoff integral calculated by using the stationary phase method, or to the eikonal. Within the paraxial approximation, we also introduce the $ABCD$ matrices formalism and the beam quality factor. As an example, we apply these tools to analyze the recent experiment by Riou et al. [Phys. Rev. Lett. 96, 070404 (2006)].

  • Theoretical tools for Atom-Laser-beam propagation
    Physical Review A, 2008
    Co-Authors: J.-f. Riou, Alain Aspect, Y. Le Coq, William Guerin, François Impens, Christian Bordé, Philippe Bouyer
    Abstract:

    We present a theoretical model for the propagation of non-self-interacting Atom Laser beams. We start from a general propagation integral equation and we use the same approximations as in photon optics to derive tools to calculate the Atom-Laser-beam propagation. We discuss the approximations that allow one to reduce the general equation whether to a Fresnel-Kirchhoff integral calculated by using the stationary phase method, or to the eikonal. Within the paraxial approximation, we also introduce the ABCD matrices formalism and the beam quality factor. As an example, we apply these tools to analyze the recent experiment.

  • Guided Atom Laser : a new tool for guided Atom optics
    Annales de Physique, 2007
    Co-Authors: Juliette Billy, Z. Zuo, W Guerin, Vincent Josse, Alain Aspect, Philippe Bouyer
    Abstract:

    We present a guided Atom Laser. A Bose-Einstein condensate (BEC) is created in a crossed hybrid magnetic and an elongated optical trap, which acts as a matterwave guide. Atoms are extracted from the BEC by radio frequency (rf) outcoupling and then guided in the horizontal optical matterwave guide. This method allows to control the acceleration of the beam and to achieve large de Broglie wavelength. We also measure the longitudinal energy of the guided Atom Laser using Atom optical elements based on a blue light barrier.

  • guided quasicontinuous Atom Laser
    Physical Review Letters, 2006
    Co-Authors: William Guerin, Vincent Josse, Philippe Bouyer, J.-f. Riou, John Gaebler, Alain Aspect
    Abstract:

    We report the first realization of a guided quasicontinuous Atom Laser by rf outcoupling a Bose-Einstein condensate from a hybrid optomagnetic trap into a horizontal Atomic waveguide. This configuration allows us to cancel the acceleration due to gravity and keep the de Broglie wavelength constant at $0.5\text{ }\text{ }\ensuremath{\mu}\mathrm{m}$ during 0.1 s of propagation. We also show that our configuration, equivalent to pigtailing an optical fiber to a (photon) semiconductor Laser, ensures an intrinsically good transverse mode matching.

John Close - One of the best experts on this subject based on the ideXlab platform.

  • Experimental comparison of Raman and rf outcouplers for high-flux Atom Lasers
    Physical Review A, 2010
    Co-Authors: John E. Debs, Cristina Figl, P A Altin, Nicholas Robins, M. Jeppesen, J Dugue, Daniel Doering, Justin T. Schultz, John Close
    Abstract:

    We study the properties of an Atom Laser beam derived from a Bose-Einstein condensate using three different outcouplers, one based on multistate radio-frequency transitions and two others based on Raman transitions capable of imparting momentum to the beam. We first summarize the differences that arise in such systems, and how they may impact on the use of an Atom Laser in interferometry. Experimentally, we examine the formation of a bound state in all three outcouplers, a phenomenon which limits the Atom Laser flux, and find that a two-state Raman outcoupler is the preferred option for high-flux, low-divergence Atom Laser beams.

  • Probing a Bose-Einstein Condensate with an Atom Laser
    Optics express, 2008
    Co-Authors: D. Döring, Cristina Figl, Nicholas Robins, John Close
    Abstract:

    A pulsed Atom Laser derived from a Bose-Einstein condensate is used to probe a second target condensate. The target condensate scatters the incident Atom Laser pulse. From the spatial distribution of scattered Atoms, one can infer important properties of the target condensate and its interaction with the probe pulse. As an example, we measure the s-wave scattering length that, in low energy collisions, describes the interaction between the |F=1,m_F=-1> and |F=2,m_F=0> hyperfine ground states in 87Rb.

  • A pumped Atom Laser
    Nature Physics, 2008
    Co-Authors: Nicholas Robins, Cristina Figl, M. Jeppesen, Graham Dennis, John Close
    Abstract:

    The experimental demonstration of a continuous and irreversible transfer of cold Atoms from a ‘source mode’ to a ‘Laser mode’ represents a step closer to a fully continuous Atom Laser.

  • Approaching the Heisenberg limit in an Atom Laser
    Physical Review A, 2008
    Co-Authors: M. Jeppesen, Cristina Figl, Nicholas Robins, Graham Dennis, Mattias Johnsson, J Dugue, John Close
    Abstract:

    We present experimental and theoretical results showing the improved beam quality and reduced divergence of an Atom Laser produced by an optical Raman transition, compared to one produced by an rf transition. We show that Raman outcoupling can eliminate the diverging lens effect that the condensate has on the outcoupled Atoms. This substantially improves the beam quality of the Atom Laser, and the improvement may be greater than a factor of 10 for experiments with tight trapping potentials. We show that Raman outcoupling can produce Atom Lasers whose quality is only limited by the wave function shape of the condensate that produces them, typically a factor of 1.3 above the Heisenberg limit.

  • Development of the Atom Laser
    2007
    Co-Authors: Nicholas Robins, Cristina Figl, M. Jeppesen, J Dugue, John Close
    Abstract:

    We discuss recent developments in our laboratory, in particular focusing on continuous Raman output coupling. We show how recent advances allow the Atom Laser beam quality to approaching the Heisenberg limit.

Joseph Hope - One of the best experts on this subject based on the ideXlab platform.

  • Quantum kinetic theory model of a continuous Atom Laser
    Physical Review A, 2012
    Co-Authors: Graham Dennis, Matthew J. Davis, Joseph Hope
    Abstract:

    We investigate the feasible limits for realizing a continuously evaporated Atom Laser with high-temperature sources. A plausible scheme for realizing a truly continuous Atom Laser is to outcouple Atoms from a partially condensed Bose gas while continuously reloading the system with noncondensed thermal Atoms and performing evaporative cooling. Here we use quantum kinetic theory to model this system and estimate feasible limits for the operation of such a scheme. For sufficiently high temperatures, the figure of merit for the source is shown to be the phase-space flux. The dominant process limiting the usage of sources with low phase-space flux is the three-body loss of the condensed gas. We conclude that certain double-magneto-optical trap sources may produce substantial mean condensate numbers through continuous evaporation and provide an Atom Laser source with a narrow linewidth and reasonable flux.

  • Paired-Atom Laser beams created via four-wave mixing
    Physical Review A, 2009
    Co-Authors: Robert Dall, Andrew Truscott, Lesa Byron, Graham Dennis, Mattias Johnsson, Joseph Hope
    Abstract:

    A method to create paired-Atom Laser beams from a metastable helium Atom Laser via four-wave mixing is demonstrated. Radio-frequency outcoupling is used to extract Atoms from a Bose-Einstein condensate near the center of the condensate and initiate scattering between trapped and untrapped Atoms. The unequal strengths of the interactions for different internal states allows an energy-momentum resonance which leads to the creation of pairs of Atoms scattered from the zero-velocity condensate. The resulting scattered beams are well separated from the main Atom Laser in the two-dimensional transverse Atom Laser profile. Numerical simulations of the system are in good agreement with the observed Atom Laser spatial profiles and indicate that the scattered beams are generated by a four-wave mixing process, suggesting that the beams are correlated.

  • Raman scheme to measure the quantum statistics of an Atom Laser beam
    Physical Review A, 2007
    Co-Authors: Ashton S. Bradley, Simon A. Haine, Murray K. Olsen, Joseph Hope
    Abstract:

    We propose and analyze a scheme for measuring the quadrature statistics of an Atom Laser beam using extant optical homodyning and Raman Atom Laser techniques. Reversal of the normal Raman Atom Laser outcoupling scheme is used to map the quantum statistics of an incoupled Atomic beam to an optical probe beam. A multimode model of the spatial propagation dynamics shows that the Raman incoupler gives a clear signal of de Broglie wave quadrature squeezing for both pulsed and continuous inputs. Finally, we show that experimental realizations of the scheme may be tested with existing methods via intensity correlation measurements.

  • Investigation and comparison of multistate and two-state Atom Laser-output couplers
    Physical Review A, 2007
    Co-Authors: J Dugue, Cristina Figl, Nicholas Robins, M. Jeppesen, Joseph Hope, Mattias Johnsson, Paul Summers, John Close
    Abstract:

    We investigate the spatial structure and temporal dynamics created in a Bose-Einstein condensate by radio-frequency Atom Laser-output couplers using a one-dimensional mean-field model. We compare the behavior of a ``pure'' two-state Atom Laser to the multilevel systems demonstrated in laboratories. In particular, we investigate the peak homogeneous output flux, classical fluctuations in the beam, and the onset of a bound state which shuts down the Atom Laser output.

  • Semiclassical limits to the linewidth of an Atom Laser
    Physical Review A, 2007
    Co-Authors: Mattias Johnsson, Cristina Figl, Nicholas Robins, Simon A. Haine, M. Jeppesen, Joseph Hope, J Dugue, John Close
    Abstract:

    We investigate the linewidth of a quasicontinuous Atom Laser within a semiclassical framework. In the high flux regime, the lasing mode can exhibit a number of undesirable features such as density fluctuations. We show that the output therefore has a complicated structure that can be somewhat simplified using Raman outcoupling methods and energy-momentum selection rules. In the weak outcoupling limit, we find that the linewidth of an Atom Laser is instantaneously Fourier limited, but, due to the energy “chirp” associated with depletion of the condensate, the long-term linewidth of an Atom Laser is equivalent to the chemical potential of the condensate source. We show that correctly sweeping the outcoupling frequency can recover the Fourier-limited linewidth.

M. Jeppesen - One of the best experts on this subject based on the ideXlab platform.

  • Experimental comparison of Raman and rf outcouplers for high-flux Atom Lasers
    Physical Review A, 2010
    Co-Authors: John E. Debs, Cristina Figl, P A Altin, Nicholas Robins, M. Jeppesen, J Dugue, Daniel Doering, Justin T. Schultz, John Close
    Abstract:

    We study the properties of an Atom Laser beam derived from a Bose-Einstein condensate using three different outcouplers, one based on multistate radio-frequency transitions and two others based on Raman transitions capable of imparting momentum to the beam. We first summarize the differences that arise in such systems, and how they may impact on the use of an Atom Laser in interferometry. Experimentally, we examine the formation of a bound state in all three outcouplers, a phenomenon which limits the Atom Laser flux, and find that a two-state Raman outcoupler is the preferred option for high-flux, low-divergence Atom Laser beams.

  • A quasi-monomode guided Atom-Laser from an all-optical Bose-Einstein condensate
    EPL - Europhysics Letters, 2008
    Co-Authors: Antoine Couvert, M. Jeppesen, Tomasz Kawalec, Gael Reinaudi, R Mathevet, David Guéry-odelin
    Abstract:

    We report the achievement of an optically guided and quasi-monomode Atom Laser, in all spin projection states ($m_F =$ $-1$, $0$ and $+1$) of $F=1$ in Rubidium 87. The Atom Laser source is a Bose-Einstein condensate (BEC) in a crossed dipole trap, purified to any one spin projection state by a spin-distillation process applied during the evaporation to BEC. The Atom Laser is outcoupled by an inhomogenous magnetic field, applied along the waveguide axis. The mean excitation number in the transverse modes is $\langle n \rangle = 0.65 \pm 0.05$ for $m_F = 0 $ and $ \langle n \rangle = 0.8 \pm 0.3$ for the low field seeker $m_F = -1$.

  • A pumped Atom Laser
    Nature Physics, 2008
    Co-Authors: Nicholas Robins, Cristina Figl, M. Jeppesen, Graham Dennis, John Close
    Abstract:

    The experimental demonstration of a continuous and irreversible transfer of cold Atoms from a ‘source mode’ to a ‘Laser mode’ represents a step closer to a fully continuous Atom Laser.

  • Approaching the Heisenberg limit in an Atom Laser
    Physical Review A, 2008
    Co-Authors: M. Jeppesen, Cristina Figl, Nicholas Robins, Graham Dennis, Mattias Johnsson, J Dugue, John Close
    Abstract:

    We present experimental and theoretical results showing the improved beam quality and reduced divergence of an Atom Laser produced by an optical Raman transition, compared to one produced by an rf transition. We show that Raman outcoupling can eliminate the diverging lens effect that the condensate has on the outcoupled Atoms. This substantially improves the beam quality of the Atom Laser, and the improvement may be greater than a factor of 10 for experiments with tight trapping potentials. We show that Raman outcoupling can produce Atom Lasers whose quality is only limited by the wave function shape of the condensate that produces them, typically a factor of 1.3 above the Heisenberg limit.

  • a quasi monomode guided Atom Laser from an all optical bose einstein condensate
    arXiv: Other Condensed Matter, 2008
    Co-Authors: Antoine Couvert, M. Jeppesen, Tomasz Kawalec, Gael Reinaudi, R Mathevet, David Gueryodelin
    Abstract:

    We report the achievement of an optically guided and quasi-monomode Atom Laser, in all spin projection states ($m_F =$ -1, 0 and $+1$) of F=1 in Rubidium 87. The Atom Laser source is a Bose-Einstein condensate (BEC) in a crossed dipole trap, purified to any one spin projection state by a spin-distillation process applied during the evaporation to BEC. The Atom Laser is outcoupled by an inhomogenous magnetic field, applied along the waveguide axis. The mean excitation number in the transverse modes is $ = 0.65 \pm 0.05$ for $m_F = 0 $ and $ = 0.8 \pm 0.3$ for the low field seeker $m_F = -1$.