Optics and Sensing Laboratory Article 2012

Evaporation-limited loading of an atomic trap

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Optics and Sensing Laboratory
Optics & Sensing Laboratory

Recently, we have experimentally demonstrated a continuous loading mechanism for an optical dipole trap from a guided atomic beam [M. Falkenau, V. V. Volchkov, J. Rührig, A. Griesmaier, and T. Pfau, Phys. Rev. Lett. 106, 163002 (2011)]. The observed evolution of the number of atoms and temperature in the trap are consequences of the unusual trap geometry. In the present paper, we develop a model based on a set of rate equations to describe the loading dynamics of such a mechanism. We consider the collision statistics in the nonuniform trap potential that leads to two-dimensional evaporation. The comparison between the resulting computations and experimental data allows to identify the dominant loss process and suggests ways to enhance the achievable steady-state atom number. Concerning subsequent evaporative cooling, we find that the possibility of controlling axial and radial confinement independently allows faster evaporation ramps compared to single beam optical dipole traps.

Author(s): Markus Falkenau and Valentin Volchkov and Jahn Rührig and Hannes Gorniaczyk and Axel Griesmaier
Journal: Physical Review A
Volume: 85
Pages: 023412
Year: 2012
Month: February
Day: 21
Publisher: American Physical Society (APS)
Bibtex Type: Article (article)
DOI: 10.1103/PhysRevA.85.023412
State: Published
Electronic Archiving: grant_archive

BibTex

@article{evaplim12,
  title = {Evaporation-limited loading of an atomic trap},
  journal = {Physical Review A},
  abstract = {Recently, we have experimentally demonstrated a continuous loading mechanism for an optical dipole trap from a guided atomic beam [M. Falkenau, V. V. Volchkov, J. Rührig, A. Griesmaier, and T. Pfau, Phys. Rev. Lett. 106, 163002 (2011)]. The observed evolution of the number of atoms and temperature in the trap are consequences of the unusual trap geometry. In the present paper, we develop a model based on a set of rate equations to describe the loading dynamics of such a mechanism. We consider the collision statistics in the nonuniform trap potential that leads to two-dimensional evaporation. The comparison between the resulting computations and experimental data allows to identify the dominant loss process and suggests ways to enhance the achievable steady-state atom number. Concerning subsequent evaporative cooling, we find that the possibility of controlling axial and radial confinement independently allows faster evaporation ramps compared to single beam optical dipole traps.},
  volume = {85},
  pages = {023412},
  publisher = {American Physical Society (APS)},
  month = feb,
  year = {2012},
  slug = {evaplim12},
  author = {Falkenau, Markus and Volchkov, Valentin and R{\"u}hrig, Jahn and Gorniaczyk, Hannes and Griesmaier, Axel},
  month_numeric = {2}
}