Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Journal de Physique IV (Proceedings)

Crossover to 2D in a double-evanescent wave trap

D. Rychtarik, B. Engeser, M. Hammes, Hanns‐Christoph Nägerl, Rudolf Grimm

Published Oct 1, 2004• 1 citation
Publisher

Abstract

\nWe report the preparation of a dense gas of cesium atoms at the\ncrossover to two-dimensionality in a highly anisotropic surface\ntrap that is realized with two evanescent light waves.\nTemperatures as low as 100 nK are reached with 20.000 atoms at a\nphase-space density close to 0.1. The lowest quantum state in the\ntightly confined direction is populated by more than 60%. The\nsystem offers intriguing prospects for future experiments on\ndegenerate quantum gases in two dimensions.\n

DOI
10.1051/jp4:2004116012

Related papers

Evanescent-Wave Trapping and Evaporative Cooling of an Atomic Gas at the Crossover to Two Dimensions

M. Hammes, D. Rychtarik, B. Engeser +2 more

A dense gas of cesium atoms at the crossover to two dimensions is prepared in a highly anisotropic surface trap that is realized with two evanescent light waves. Temperatures as low as 100 nK are reached with 20,000 atoms at a phase-space density close to 0.1. The lowest quantum state in the tightly confined direction is populated by more than 60%. The system provides atoms at a mean distance from the surface as low as 1 microm, and offers intriguing prospects for future experiments on degenerate quantum gases in two dimensions.

arXiv:physics/0208065•Physical Review Letters•Apr 29, 2003•60 citations

Evanescent-wave trapping of Cs at the crossover to two-dimensionality

D. Rychtarik, B. Engeser, M. Hammes +2 more

Summary form only given. Our experiment aims at investigating a two-dimensional degenerate quantum gas of cesium atoms. For this purpose, we exploit a double evanescent-wave trap (DEW trap) consisting of a repulsive and an attractive evanescent wave and providing a highly anisotropic dipole potential. Efficient loading is accomplished by a multi-stage sequence. Cesium atoms are laser cooled in a MOT and then transferred into a gravito-optical dipole trap that serves as a surface reservoir. In the next stage, the phase-space density is enhanced by creating a dimple in the potential with a far-detuned, attractive laser beam that is focused to the center of the reservoir. Finally, we transfer the atoms into the DEW trap. The vertical dipole potential provides a well close to the surface, and depends on the power of the attractive evanescent wave. Ramping down the power of the attractive evanescent wave leads to efficient evaporation. A situation at the crossover to two-dimensionality is reached when the thermal energy of k/sub B/ /spl times/ 100 nK equals the level spacing h/spl nu/; thus the vertical ground state is populated by over 60 percent. Since the final phase-space density is as high as 0.1, the creation of a degenerate two-dimensional quantum gas of Cs comes into experimental reach. In present experiments we polarize the atoms into the F = 3, m/sub F/ = 3 state. As a consequence of the resonant interaction properties of cesium, the scattering length can be tuned in a wide range by applying a magnetic field. We use the tunability of interactions to optimize the evaporation efficiency on the way to a two-dimensional degenerate quantum gas of cesium.

European Quantum Electronics Conference (EQEC)•Jan 1, 2003•0 citations

Two-dimensional quantum gas in a hybrid surface trap

Jonathon I. Gillen, Waseem Bakr, Amy Peng +3 more

We demonstrate the realization of a two-dimensional (2D) quantum gas in a smooth optical surface trap. Using a combination of evanescent wave, standing wave, and magnetic potentials, we create a long-lived quantum gas deep in the 2D regime at a distance of a few microns from a glass surface. To realize a system suitable for many-body quantum simulation, we introduce methods such as broadband ``white'' light to create evanescent and standing waves to realize a smooth potential with a trap frequency aspect ratio of 300:1:1. We are able to detect phase fluctuations and vortices, and we demonstrate cooling to degeneracy and low disorder in the 2D configuration.

arXiv:0812.3630•Physical Review A•Aug 14, 2009•36 citations

Cold atoms near a surface

Tilman Pfau, H. Gauck, Dominik Schneble +3 more

Two-dimensional systems are of great interest in physics as the celebrated quantum-Hall effects show, which are based on a 2D electron gas. Neutral systems involve thin He films and spin polarized atomic hydrogen in a cryogenic environment, where the successful creation of a 2D quasi-condensate was recently reported. Over the last years, with laser cooling and trapping techniques at hand, several schemes for the preparation of laser cooled atomic 2D gases have been proposed. Low dimensional gases are discussed as keys to achieve high density samples of purely optically cooled atoms, since the reabsorption of scattered photons is greatly suppressed compared to the situation in 3D. On the other hand, by structuring 2D waveguide light fields laterally, very versatile "integrated atom optical" elements can be realized. We have prepared a quasi-2D gas of argon atoms confined in a planar matter waveguide less than 1 /spl mu/m away from a reflecting surface. We trap metastable Ar/sup +/ atoms in the ls/sub 5/(J=2) state in a magneto-optical trap. Upon release, they fall towards a gold coated prism surface where an evanescent light field is generated by resonant excitation of surface plasmons in the gold layer. This light field is blue detuned from the 1s/sub 5//spl hArr/2p/sub 9/(J=3) transition and hence creates a repulsive potential which slows down the falling atoms.

Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR)•Jan 20, 2003•0 citations

Cold-atom gas at very high densities in an optical surface microtrap

M. Hammes, D. Rychtarik, Hanns‐Christoph Nägerl +1 more

An optical microtrap is realized on a dielectric surface by crossing a tightly focused laser beam with a horizontal evanescent-wave atom mirror. The nondissipative trap is loaded with $\ensuremath{\sim}{10}^{5}$ cesium atoms through elastic collisions from a cold reservoir provided by a large-volume optical surface trap. With an observed 300-fold local increase of the atomic number density approaching ${10}^{14}{\mathrm{cm}}^{\ensuremath{-}3},$ unprecedented conditions of cold atoms close to a surface are realized.

arXiv:physics/0204026•Physical Review A•Nov 14, 2002•30 citations

Quasi two-dimensional gas of ultracold argon atoms close to a surface

H. Gauck

We prepare a quasi 2D gas of ultracold argon atoms confined in a planar matter waveguide in close vicinity (< 1µm) of a reflecting surface. The (anti-)nodes of a far off resonant standing light wave in front of the surface provide a confining potential for the atomic motion normal to the surface. A cloud of cold atom that approaches the surface is compressed by deceleration in an evanescent field and loaded predominantly into one single potential well close to the surface by optical pumping. The spatial density achieved is more than 100 times higher than the density of the approaching atoms.

•Jan 1, 1999•0 citations
\nWe report the preparation of a dense gas of cesium atoms at the\ncrossover to two-dimensionality in a highly anisotropic surface\ntrap that is realized with two evanescent light waves.\nTemperatures as low as 100 nK are reached with 20.000 atoms at a\nphase-space density close to 0.1. The lowest quantum state in the\ntightly confined direction is populated by more than 60%. The\nsystem offers intriguing prospects for future experiments on\ndegenerate quantum gases in two dimensions.\n
A dense gas of cesium atoms at the crossover to two dimensions is prepared in a highly anisotropic surface trap that is realized with two evanescent light waves. Temperatures as low as 100 nK are reached with 20,000 atoms at a phase-space density close to 0.1. The lowest quantum state in the tightly confined direction is populated by more than 60%. The system provides atoms at a mean distance from the surface as low as 1 microm, and offers intriguing prospects for future experiments on degenerate quantum gases in two dimensions.
Summary form only given. Our experiment aims at investigating a two-dimensional degenerate quantum gas of cesium atoms. For this purpose, we exploit a double evanescent-wave trap (DEW trap) consisting of a repulsive and an attractive evanescent wave and providing a highly anisotropic dipole potential. Efficient loading is accomplished by a multi-stage sequence. Cesium atoms are laser cooled in a MOT and then transferred into a gravito-optical dipole trap that serves as a surface reservoir. In the next stage, the phase-space density is enhanced by creating a dimple in the potential with a far-detuned, attractive laser beam that is focused to the center of the reservoir. Finally, we transfer the atoms into the DEW trap. The vertical dipole potential provides a well close to the surface, and depends on the power of the attractive evanescent wave. Ramping down the power of the attractive evanescent wave leads to efficient evaporation. A situation at the crossover to two-dimensionality is reached when the thermal energy of k/sub B/ /spl times/ 100 nK equals the level spacing h/spl nu/; thus the vertical ground state is populated by over 60 percent. Since the final phase-space density is as high as 0.1, the creation of a degenerate two-dimensional quantum gas of Cs comes into experimental reach. In present experiments we polarize the atoms into the F = 3, m/sub F/ = 3 state. As a consequence of the resonant interaction properties of cesium, the scattering length can be tuned in a wide range by applying a magnetic field. We use the tunability of interactions to optimize the evaporation efficiency on the way to a two-dimensional degenerate quantum gas of cesium.
We demonstrate the realization of a two-dimensional (2D) quantum gas in a smooth optical surface trap. Using a combination of evanescent wave, standing wave, and magnetic potentials, we create a long-lived quantum gas deep in the 2D regime at a distance of a few microns from a glass surface. To realize a system suitable for many-body quantum simulation, we introduce methods such as broadband ``white'' light to create evanescent and standing waves to realize a smooth potential with a trap frequency aspect ratio of 300:1:1. We are able to detect phase fluctuations and vortices, and we demonstrate cooling to degeneracy and low disorder in the 2D configuration.
Two-dimensional systems are of great interest in physics as the celebrated quantum-Hall effects show, which are based on a 2D electron gas. Neutral systems involve thin He films and spin polarized atomic hydrogen in a cryogenic environment, where the successful creation of a 2D quasi-condensate was recently reported. Over the last years, with laser cooling and trapping techniques at hand, several schemes for the preparation of laser cooled atomic 2D gases have been proposed. Low dimensional gases are discussed as keys to achieve high density samples of purely optically cooled atoms, since the reabsorption of scattered photons is greatly suppressed compared to the situation in 3D. On the other hand, by structuring 2D waveguide light fields laterally, very versatile "integrated atom optical" elements can be realized. We have prepared a quasi-2D gas of argon atoms confined in a planar matter waveguide less than 1 /spl mu/m away from a reflecting surface. We trap metastable Ar/sup +/ atoms in the ls/sub 5/(J=2) state in a magneto-optical trap. Upon release, they fall towards a gold coated prism surface where an evanescent light field is generated by resonant excitation of surface plasmons in the gold layer. This light field is blue detuned from the 1s/sub 5//spl hArr/2p/sub 9/(J=3) transition and hence creates a repulsive potential which slows down the falling atoms.
An optical microtrap is realized on a dielectric surface by crossing a tightly focused laser beam with a horizontal evanescent-wave atom mirror. The nondissipative trap is loaded with $\ensuremath{\sim}{10}^{5}$ cesium atoms through elastic collisions from a cold reservoir provided by a large-volume optical surface trap. With an observed 300-fold local increase of the atomic number density approaching ${10}^{14}{\mathrm{cm}}^{\ensuremath{-}3},$ unprecedented conditions of cold atoms close to a surface are realized.
We prepare a quasi 2D gas of ultracold argon atoms confined in a planar matter waveguide in close vicinity (< 1µm) of a reflecting surface. The (anti-)nodes of a far off resonant standing light wave in front of the surface provide a confining potential for the atomic motion normal to the surface. A cloud of cold atom that approaches the surface is compressed by deceleration in an evanescent field and loaded predominantly into one single potential well close to the surface by optical pumping. The spatial density achieved is more than 100 times higher than the density of the approaching atoms.