https://doi.org/10.1007/s100530050122
Temporal coherent control induced by wave packet interferences in one and two photon atomic transitions
1
Laboratoire de Collisions Agrégats Réactivité, C.N.R.S. (UMR 5589) ,
IRSAMC,
Université Paul Sabatier, 118 Route de Narbonne, 31062 Toulouse Cedex,
France
2
Freie Universität Berlin, Experimentalphysik, Arnimallee 14, 14169 Berlin,
Germany
Corresponding author: a bertrand@yosemite.ups-tlse.fr
Received:
30
December
1997
Revised:
28
February
1998
Accepted:
4
March
1998
Published online: 15 May 1998
The interaction of a sequence of two identical ultrashort laser pulses with an
atomic system results in quantum interferences as in Ramsey fringes experiments.
These interferences allow achievement of temporal coherent control of the excitation
probability. We present the results of a temporal coherent control experiment on two
different atomic systems: one-photon absorption in K () and two-photon absorption
in Cs (
). In K, the quantum interferences between the two excitation paths
associated with the laser pulses are revealed through rapid oscillations of the excitation
probability as a function of the time delay between the two pulses. These oscillations
take place at the transition frequency (period T = 2.56 fs). The interferences are
modulated by beats (at about 580 fs) resulting from the doublet structure of the excited
state (4p (
)). Three complementary interpretations of this experiment are
presented: in terms of beats of quantum interferences, of variation in the spectrum
intensity, and of wave packet interferences. Whenever the two laser pulses are
temporally overlapped, optical interferences are superimposed on to the quantum
interferences. The distinction between these two types of interference is clearly revealed
in the two-photon excitation scheme performed on Cs (
(
)) because
quantum interferences occur at twice the frequency of the optical interferences.
PACS: 32.80.Qk – Coherent control of atomic interactions with photons / 32.80.Rm – Multiphoton ionization and excitation to highly excited states (e.g., Rydberg states) / 42.50.Md – Optical transient phenomena: quantum beats, photon echo, free-induction decay, dephasings and revivals, optical nutation, and self-induced transparency
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1998