Atom slowing via dispersive optical interactions

Science, 2009

Applied Physics B: …, 2010

We report on a slow guided atom laser beam outcoupled from a Bose-Einstein condensate of 87 Rb atoms in a hybrid trap. The acceleration of the atom laser beam can be controlled by compensating the gravitational acceleration and we reach residual accelerations as low as 0.0027 g. The outcoupling mechanism allows for the production of a constant flux of 4.5 × 10 6 atoms per second and due to transverse guiding we obtain an upper limit for the mean beam width of 4.6 µm. The transverse velocity spread is only 0.2 mm/s and thus an upper limit for the beam quality parameter is M 2 = 2.5. We demonstrate the potential of the long interrogation times available with this atom laser beam by measuring the trap frequency in a single measurement. The small beam width together with the long evolution and interrogation time makes this atom laser beam a promising tool for continuous interferometric measurements. arXiv:1005.3964v1 [cond-mat.quant-gas]

Optics Communications, 1995

The force resulting from a position-dependent sequence of interactions with short counter-propagating n--pulses of laser radiation can propel atoms towards the small region where the pulses overlap. The optical trap thus formed may be combined with Doppler-cooling laser beams.

Physical Review A, 1997

We have developed a diagnostic tool for the study of Zeeman-compensated slowing of an alkali-metal atomic beam. Our time-of-flight technique measures the longitudinal velocity distribution of the slowed atoms with a resolution below the Doppler limit. Furthermore, it can map the position and velocity distribution of atoms in either ground hyperfine level inside the solenoid without any devices inside the solenoid. The technique reveals the optical pumping effects and shows in detail how the slowing within the solenoid proceeds. We find for Na that most atoms in the chosen hyperfine state are decelerated in the slowing process. The width of the velocity distribution is determined mainly by inhomogeneities in the slowing laser beam. Using the central most uniform part of an expanded laser beam, the width is reduced to 2.5 m/s, corresponding to 3.2 mK. Finally, we discuss and show a method to produce a beam with two-velocity components for the study of head-tail low-energy collisions. ͓S1050-2947͑97͒03101-6͔

Journal of the Optical Society of America B, 2002

Based on realistic numerical simulations of atomic hydrogen interacting with high-frequency ultraintense laser pulses, we show an optimized laser scheme for an experiment on atomic stabilization. A single traveling wave does not constitute an appropriate experimental arrangement, provided that the magnetic drift (the radiation pressure) plays a fundamental role in governing the dynamics of the wave packet in this range of laser parameters. There is, however, a possible experiment where this undesired effect of the magnetic field can be eliminated: our proposal is that the incoming field has to be split into two counterpropagating fields with certain polarization conditions.

Physical Review A, 2000

We describe a versatile method for slowing molecules ͑or atoms͒ which relies on high-field-seeking states created by the polarizability interaction with a nonresonant laser field. A pulsed supersonic beam expansion is employed to precool the molecules internally and to narrow their velocity spread. The molecules are scooped at right angles by a nonresonant laser beam steered by a scanner and decelerated on a circular path by gradually reducing the beam's angular speed.

New Journal of Physics, 2006

A supersonic beam of noble gas atoms is a source of unprecedented brightness.A novel short pulse supersonic nozzle is developed with beam intensity that is higher by at least an order of magnitude than other available sources. We show how this beam can be coherently slowed and focused using elastic reflection from single crystals. Simulations show beam fluxes of 10 11 atoms s -1 at velocities of 50 m s -1 and temperatures of less than 20 µK in the longitudinal direction. Possible applications of this slow beam to the study of atom-surface interactions and atom interferometry are discussed.

Europhysics News, 2004

Physical Review Letters, 1992

We demonstrate cooling and slowing of atoms in isotropic laser light. As the atoms slow, they compensate for their changing Doppler shift by preferentially absorbing photons at a varying angle to their direction of motion, resulting in a continuous beam of slow atoms unperturbed by an intense slowing laser beam. We point out several novel features of slowing and cooling in isotropic light, and show that it can be superior to cooling with directed laser beams.

New Journal of Physics, 2015

We propose a method of stimulated laser decelerating of diatomic molecules by counter-propagating π-trains of ultrashort laser pulses. The decelerating cycles occur on the rovibrational transitions inside the same ground electronic manifold, thus avoiding the common problem of radiative branching in Doppler cooling of molecules. By matching the frequency comb spectrum of the pulse trains to the spectrum of the R-branch rovibrational transitions we show that stimulated deceleration can be carried out on several rovibrational transitions simultaneously. This enables an increase in the number of cooled molecules with only a single laser source. The exerted optical force does not rely on the decay rates in a system and can be orders of magnitude larger than the typical values of scattering force obtained in conventional Doppler laser cooling schemes.

Zeitschrift f�r Physik B Condensed Matter, 1992

The propagation of strong and short laser pulses in a medium of two-level atoms is numerically investigated. The spontaneous and collisional relaxation rates are taken into account. The behavior of the pulse envelope and its Fourier transform is studied in connection with the area theorem and formation of the 2ng-pulses. Particularly, sudden transitions from 2n~ value of the pulse area to 2(n-1)zc are predicted. This effect is associated by a sudden change of the energy losses per unit distance.

Physical Review A, 2009

We develop a systematic formalism to study the propagation of a guided probe light field along a nanofiber embedded in a cold atomic gas. We derive a general axial propagation equation for the amplitude of the photon flux of the guided light, which allows us to take into account the complexity of the guided-field vector structure and the evanescent-wave nature of the guided-field transverse profile. We use our formalism to explore the possibility of slowing down of the guided light via the process of electromagnetically induced transparency. We show that, despite the effects of the spatially varying detuning, caused by the van der Waals potential, and the spatially varying atom-field coupling, caused by the evanescent-wave nature of the guided mode in the transverse plane, the group velocity of the guided light can be substantially reduced due to the steep dispersion of the atomic gas in the condition of electromagnetically induced transparency.

An iterative predictor-corrector finite-difference time-domain method is used to solve the semiclassical Maxwell-Bloch system numerically without invoking any of the standard approximations such as the rotating-wave approximation. This approach permits a more exact study of self-induced transparency effects in a two-level atom. In addition to recovering the standard results, for instance, for vr, 2~, and 4m pulses, several. features in the results appear at the zeros of the driving pulse, where its time derivatives are maximum. Several ultrafast-pulse examples demonstrate that time-derivative-driven nonlinearities have a significant impact on the time evolution of a two-level atom system. Moreover, typical small-signal gain results are also obtained with our Maxwell-Bloch simulator. We illustrate that these time-derivative effects can be used to design an ultrafast, single-cycle pump pulse that completely inverts the two-level atom population. A pump-probe signal set is then used to illustrate gain in the probe signal.

Journal of The Optical Society of America B-optical Physics, 1998

The application of counterpropagating, short, chirped laser pulses for the deflection and splitting of an atomic beam is investigated. A simple model is proposed to describe the case in which the pulses induce population transfer in the adiabatic-passage regime and in which the effects of spontaneous emission are negligible during the action of a single laser pulse. Spontaneous emission between the pulses is not neglected, however, and it is shown that it has a significant effect on the evolution of the average transversal velocity of the atoms, as well as the dispersion of the transversal velocity.

Journal of the Optical Society of America B, 1989

We have observed that the transverse guiding that results when an intense light field with a Gaussian intensity distribution is superimposed upon an atomic beam can increase the total number of atoms in the beam and select atoms according to transverse velocity. This guiding preferentially retains atoms with small longitudinal velocities;