Adiabatic excitation of rotational ladder by chirped laser pulses

Journal Article · Mon Mar 01 04:00:00 EST 2004 · Physical Review. A

DOI:https://doi.org/10.1103/PhysRevA.69.033409· OSTI ID:20640875

Vitanov, N V; Girard, B ^[1]

---

1. Department of Physics Sofia University, James Boucher 5 Boulevard, 1164 Sofia (Bulgaria)

We discuss rotational excitation of molecules by a pair of left and right circularly polarized laser pulses with opposite chirps. The pulses are supposed to be short enough (picosecond or femtosecond) to prevent relaxation, sufficiently intense to induce adiabatic evolution, and far-off-resonant, e.g., infrared. This technique has been demonstrated recently by Villeneuve et al. [Phys. Rev. Lett. 85, 542 (2000)] in rotational dissociation of molecules. We analyze the properties of this technique by using the concepts of level crossing and adiabatic evolution, which allow us to derive analytically the conditions for efficient excitation. We analyze both the cases of intuitive (divergent frequencies) and counterintuitive (convergent frequencies) chirps and examine various initial conditions, including a single J state, coherent and incoherent superpositions of J states. We propose a technique, which can create superrotors by applying a pair of appropriately timed narrow pulses.

• OSTI ID: 20640875
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 3 Vol. 69; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
DISSOCIATION
EVOLUTION
EXCITATION
LASER RADIATION
LASERS
MODULATION
MOLECULES
PULSES
RELAXATION
ROTATIONAL STATES