Optical Confinement of a Bose-Einstein Condensate

TLDR

Sodium Bose‑Einstein condensates were confined in an optical dipole trap formed by a single focused infrared laser beam, removing the limitations of magnetic traps and enabling further atom‑laser studies. The optical trap held over 5×10⁶ atoms at densities up to 3×10¹⁵ cm⁻³, allowing measurement of the three‑body loss rate constant K₃ = 1.1(3)×10⁻³⁰ cm⁶ s⁻¹; at lower densities the 1/e lifetime exceeded 10 s, and condensates in multiple hyperfine states were simultaneously confined.

Abstract

Bose-Einstein condensates of sodium atoms have been confined in an optical dipole trap using a single focused infrared laser beam. This eliminates the restrictions of magnetic traps for further studies of atom lasers and Bose-Einstein condensates. More than $5\ifmmode\times\else\texttimes\fi{}{10}^{6}$ condensed atoms were transferred into the optical trap. Densities of up to $3\ifmmode\times\else\texttimes\fi{}{10}^{15}{\mathrm{cm}}^{\ensuremath{-}3}$ of Bose condensed atoms were obtained, allowing for a measurement of the three-body loss rate constant for sodium condensates as ${K}_{3}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.1(3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}30}{\mathrm{cm}}^{6}{\mathrm{s}}^{\ensuremath{-}1}$. At lower densities, the observed $1/e$ lifetime was longer than 10 s. Simultaneous confinement of Bose-Einstein condensates in several hyperfine states was demonstrated.