Experiments with Supersonic Beams as a Source of Cold Atoms

General Methods of Controlling Atomic Motion:
Experiments with Supersonic Beams as a Source of Cold
Atoms
Adam Alexander Libson, Ph.D.
The University of Texas at Austin, 2012
Supervisor: Mark G. Raizen
This dissertation discusses several recently developed experimental techniques
for controlling the motion of neutral atoms. While laser cooling and evaporative
cooling have been extremely successful and have been in widespread use for many
years, these techniques are only applicable to a few atomic species. Supersonic beams
provide a general method of producing cold atoms in the co-moving frame, but their
speeds are typically several hundreds of meters per second in the lab frame. Methods
to slow and control atoms cooled by supersonic expansion are detailed.
A method for controlling the velocity of a cold beam of ground state helium
using specular reflection from single crystal surfaces is demonstrated. The velocity of
the beam is shown to be continuously tunable, and beam velocities as slow as 265m/s
are created from an initial beam speed of 511 m/s.
Magnetism is a nearly universal atomic phenomenon, making magnetic control
of atomic motion a very general technique. Magnetic stopping of supersonic beams
of metastable neon and molecular oxygen is demonstrated using a series of pulsed
electromagnetic coils. Neon is slowed from 446 m/s to 56 m/s, and oxygen is slowed
from 389 m/s to 83 m/s, removing over 95% of the kinetic energy. The experimental
technique is described in detail, and the theory and principle are discussed. An
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