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Coherent control on atoms and small molecules

- Observation and manipulation of Coherent Transients :

The principle and experimental demonstration of time resolved quantum state holography has been demonstrated. The quantum state of an excited state interacting with an ultrashort chirped laser pulse is measured during this interaction. This has been obtained by manipulating coherent transients created by the interaction of femtosecond shaped pulses and rubidium atoms.

References :

- S. Zamith, J. Degert, S. Stock, B. de Beauvoir, V. Blanchet,
M. Bouchene, and B. Girard.
Observation of coherent transients in ultrashort chirped excitation of an undamped two-level system.
Phys. Rev. Lett., 87(3):033001, 2001.

- J. Degert, W. Wohlleben, B. Chatel, M. Motzkus, and B. Girard.
Realization of a time-domain fresnel lens with coherent control.
Phys. Rev. Lett., 89(20):203003, 2002.

- A. Monmayrant, B. Chatel, and B. Girard.
Femtosecond pulse shape reconstruction from coherent transient measurements.
Opt. Lett., 31:410, (2006).

- A. Monmayrant, B. Chatel, and B. Girard.
Atomic spirograph : measurement of the excited state wave function using coherent transients.
Phys. Rev. Lett., 96:103002, 2006.

- A. Monmayrant, B. Chatel, and B. Girard.
Real time quantum state holography using coherent transients.
Opt. Commun., 264(2):256, 2006.

- B. Chatel, D. Bigourd, S. Weber, and B. Girard.
Coherent control of spin-orbit precession with shaped laser pulses.
J. Phys. B, 41(7):074023, 2008. 0953-4075.

- Observation of quantum interferences in ladder climbing :

Two-photon excitation of a quantum ladder system by a chirped pulse leads to interferences in the excited state population, due to the phase differences between direct and sequential paths. First, based on an analytical approach, we separate and discuss the features of the contributions arising from these two paths. Then interferences
with two intermediate levels are observed experimentally in atomic sodium vapor. Interplay between the two sequential paths leads to strongly contrasted oscillations and a great enhancement of the transition
probability for some values of the chirp.

References :

- B. Chatel, J. Degert and B. Girard
Role of quadratic and cubic spectral phases in ladder climbing with ultrashort pulses
Phys. Rev. A 70, 053414 (2004).
- B. Chatel, J. Degert, S. Stock and B. Girard
Competition between sequential and direct paths in a two-photon transition
Phys. Rev. A 68, 041402 (2003).

- Wavepacket interferences :

Reference :

- Katsuki et al, PRL 102, 103602 (2009)