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Journal of the Optical Society of America B

Journal of the Optical Society of America B


  • Editor: Henry van Driel
  • Vol. 29, Iss. 3 — Mar. 1, 2012
  • pp: 475–483

Magneto-optical trap loading rate dependence on trap depth and vapor density

Magnus Haw, Nathan Evetts, Will Gunton, Janelle Van Dongen, James L. Booth, and Kirk W. Madison  »View Author Affiliations

JOSA B, Vol. 29, Issue 3, pp. 475-483 (2012)

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We study the dependence of the particle loading rate of a rubidium vapor cell magneto-optic trap (MOT). Using a trap depth determination of the MOT that relies on measurements of loss rates during optical excitation of colliding atoms to a repulsive molecular state, we experimentally determine the MOT escape velocity and show that the loading rate scales with escape velocity to the fourth power, or, equivalently, with the square of the trap depth. We also demonstrate that the loading rate is directly proportional to the background rubidium density. We thus experimentally confirm the loading rate model used in the literature since the invention of the MOT. In addition to confirming this long-standing conjecture, we show that the loading rate dependence can be used to reliably infer the trap depth and to tune the relative depth of a MOT (i.e., capture and escape velocities) when the background density is held fixed. The measurements have allowed an experimental determination of the relationship between capture and escape velocities in our MOTs of vc=1.29(0.12)ve.

© 2012 Optical Society of America

OCIS Codes
(020.2070) Atomic and molecular physics : Effects of collisions
(020.7010) Atomic and molecular physics : Laser trapping
(020.3320) Atomic and molecular physics : Laser cooling

ToC Category:
Atomic and Molecular Physics

Original Manuscript: September 27, 2011
Manuscript Accepted: November 16, 2011
Published: February 28, 2012

Magnus Haw, Nathan Evetts, Will Gunton, Janelle Van Dongen, James L. Booth, and Kirk W. Madison, "Magneto-optical trap loading rate dependence on trap depth and vapor density," J. Opt. Soc. Am. B 29, 475-483 (2012)

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