Eur. Phys. J. D 21, 347-351 (2002)
https://doi.org/10.1140/epjd/e2002-00205-1

Cold trapped atoms detected with evanescent waves

Van der Waals–Zeeman Institute, University of Amsterdam, Valckenierstraat 65, 1018 XE Amsterdam, The Netherlands

Corresponding author: ^a spreeuw@science.uva.nl

Received: 14 May 2002
Published online: 8 October 2002

Abstract

We demonstrate the in situ detection of cold ⁸⁷Rb atoms near a dielectric surface using the absorption of a weak, resonant evanescent wave. We have used this technique in time of flight experiments determining the density of atoms falling on the surface. A quantitative understanding of the measured curve was obtained using a detailed calculation of the evanescent intensity distribution. We have also used it to detect atoms trapped near the surface in a standing-wave optical dipole potential. This trap was loaded by inelastic bouncing on a strong, repulsive evanescent potential. We estimate that we trap atoms at a density 100 times higher than the falling atoms.