60 research outputs found
Atom interferometer as a selective sensor of rotation or gravity
In the presence of Earth gravity and gravity-gradient forces, centrifugal and
Coriolis forces caused by the Earth rotation, the phase of the time-domain atom
interferometers is calculated with accuracy up to the terms proportional to the
fourth degree of the time separation between pulses. We considered double-loop
atom interferometers and found appropriate condition to eliminate their
sensitivity to acceleration to get atomic gyroscope, or to eliminate the
sensitivity to rotation to increase accuracy of the atomic gravimeter.
Consequent use of these interferometers allows one to measure all components of
the acceleration and rotation frequency projection on the plane perpendicular
to gravity acceleration. Atom interference on the Raman transition driving by
noncounterpropagating optical fields is proposed to exclude stimulated echo
processes which can affect the accuracy of the atomic gyroscopes. Using
noncounterpropagating optical fields allows one to get a new type of the Ramsey
fringes arising in the unidirectional Raman pulses and therefore centered at
the two-quantum line center. Density matrix in the Wigner representation is
used to perform calculations. It is shown that in the time between pulses, in
the noninertial frame, for atoms with fully quantized spatial degrees of
freedom, this density matrix obeys classical Liouville equations.Comment: 21 pages, 4 figures, extended references, discussion, and motivatio
Matter wave interference using two-level atoms and resonant optical fields
A theory of matter wave interference is developed in which resonant optical
fields interact with two-level atoms. When recoil effects are included, spatial
modulation of the atomic density can occur for times that are greater than or
comparable with the inverse recoil frequency. In this regime, the atoms exhibit
matter-wave interference. Two specific atom field geometries are considered. In
the first, atoms characterized by a homogeneous velocity distribution are
subjected to a single radiation pulse. The pulse excites the atoms which then
decay back to the lower state. The spatial modulation of the total atomic
density is calculated as a function of , where is the time following the
pulse. In contrast to the normal Talbot effect, the spatially modulated density
is not a periodic function of owing to spontaneous emission; however,
after a sufficiently long time, the contribution from spontaneous processes no
longer plays a role and the Talbot periodicity is restored. In the second
atom-field geometry, there are two pulses separated by an interval . The
atomic velocity distribution in this case is assumed to be inhomogeneously
broadened. In contrast to the normal Talbot-Lau effect, the spatially modulated
density is not a periodic function of , owing to spontaneous emission;
however, for sufficiently long time, the contribution from spontaneous
processes no longer plays a role and the Talbot periodicity is restored. The
structure of the spatially modulated density is studied, and is found to mirror
the atomic density following the first pulse. The spatially modulated atomic
density serves as an indirect probe of the distribution of spontaneously
emitted radiation.Comment: 14 pages, 3 figure
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