Single-Photon Atomic Cooling - Raizen Lab - The University of ...

quency regime [19]. This then led to the question of whether an analogous
asymmetric barrier could be constructed for neutral atoms, and furthermore,
whether such a device could be used to cool an atomic sample.
The answer to both of these questions was yes. In December 2004
and February 2005, papers were published outlining methods of producing
asymmetric barriers optically for neutral atoms. While conceived at nearly
the same time, these two methods were arrived at independently and differ
from each other in several ways.
In a paper authored by A. Ruschhaupt and J.G. Muga [20], an optical
asymmetric barrier was considered in the context of atomic control but not
cooling.. It discussed a possible implementation of an “atom diode,” a device
that rectifies the motion of neutral atoms by letting ground-state atoms pass
in one direction but not in the opposite direction. This process relied on
stimulated Raman adiabatic passage (STIRAP) and only worked over a limited
atomic velocity range. It required the use of three lasers: two to achieve the
adiabatic transfer and the third to reflect the ground state atoms. While
interesting for its use in atomic control, this paper did not consider using the
diode for atomic cooling. These authors later collaborated with M.G. Raizen
on a paper describing a version of the atomic diode which used a “quenching”
beam to improve performance [21].
Independent work came from our group and also described a method
of constructing an asymmetric one-way barrier for neutral atoms [22]. The
details of the proposal differed from that of A. Ruschhaupt and J.G. Muga
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