Frankfurt 2006 – scientific programme

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MO: Molekülphysik

MO 51: Molecular Quantum Control

MO 51.2: Talk

Thursday, March 16, 2006, 10:55–11:10, H12

Pulse shaping control of spatially aligned rotational wavepackets of N₂ and O₂ — •Christian Horn¹, Marc Krug¹, Matthias Wollenhaupt¹, Thomas Baumert¹, Rebeca de Nalda², Florian Ausfelder², and Luis Banares² — ¹Universität Kassel, Institut für Physik und Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), Heinrich-Plett-Str. 40, D-34132 Kassel, Germany — ²Dpto. Química Física I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid, Spain

Molecular alignment induced by ultrashort laser pulses has proven to be a powerful tool to create spatially aligned distributions in an otherwise randomly oriented, gaseous sample of molecules. The field-free alignment occurring at revivals of the rotational wave-packet is characterized by very fast dynamics where diatomic molecules oscillate between the situation of alignment (molecular axis preferentially oriented along the direction of the laser polarization vector) and anti-alignment, where the molecular axis preferentially lies in the plane perpendicular to the polarization vector. Previous theoretical and experimental work has been devoted to affect the magnitude and intensity of such revivals by using either pairs, or sequences of pulses. A much more general approach to control is the use of pulse-shaping techniques. We show that phase-only shaping of pulses can be successfully applied to the control of alignment revivals. Specifically we are able to enhance alignment at the expense of anti-alignment or vice versa at a given revival by applying a suitable phase mask to the aligning laser pulse. The results of the experiment are compared with numerical simulations.