Cesium atoms are also relatively heavy and thus move at a relatively slow speed of about 130 m/s at room temperature in an atomic beam
. This allows cesium atoms to be observed for a longer period than hydrogen atoms, for example, which travel much faster, about 1600 m/s, at room temperature.
"This represents a first demonstration of a significant step forward in atomic beam
For the artifact discussed here, the Cr atomic beam
was mechanically collimated with a 0.3 mm x 1 mm slit and transversely cooled to a half-angle divergence of 0.08 mrad.
More recently, a second team has observed lasing without inversion in a sodium atomic beam
Because of the velocity spread in the atomic beam
, this separation is not perfect, so some atoms in other [m.sub.F] states are mixed in with the ground-state atoms that go through the cav ity.
In other words, the atomic beam
acts as a kind of cleaning agent.
In one such device, a calcium atomic beam
is divided into four wave paths by two laser beams perpendicular to the atoms.
Ramsey's approach of imposing two separate, oscillating electromagnetic fields on an atomic beam
to induce energy-level transitions formed the basis for the cesium atomic clock, which sets the present time standard.
Grisham is a world leader in the development of high-power atomic beams
based on the production of the unusual negatively charged hydrogen ion.
They also suggest ways of constructing such gates out of quantum dots, atomic beams
, or trapped ions interacting with laser beams.
Metcalf predicts this method wil not only improve the quality of experiments involving atomic beams
, atomic fountains (SN: 8/19/89, p.117) and laser colling (SN: 8/12/89, p.103) but also will help make possible the development of extremely precise atomic clocks and atomic gyroscopes.
This should yield an effect about 1,000 times larger, but experimentalists have not yet devised a way to produce atomic beams
with the right characteristics for such an experiment.