Optical gratings induced by field-free alignment of molecules

A. Rouzee (1, 2) , V. Renard (1, 2) , S. Guerin (1, 2) , O. Faucher (1, 2) , B. Lavorel (1, 2)

1 LPUB - Laboratoire de Physique de l'Université de Bourgogne
2 ICB - Laboratoire Interdisciplinaire Carnot de Bourgogne

We analyze the alignment of molecules generated by a pair of crossed ultra-short pump pulses of different polarizations by a technique based on the induced time-dependent gratings. Parallel polarizations yield an intensity grating, while perpendicular polarizations induce a polarization grating. We show that both configurations can be interpreted at moderate intensity as an alignment induced by a single polarized pump pulse. The advantage of the perpendicular polarizations is to give a signal of alignment that is free from the plasma contribution. Experiments on femtosecond transient gratings with aligned molecules were performed in CO2 at room temperature in a static cell and at 30 K in a molecular expansion jet.

Domaines: Optique [physics.optics]

A. Rouzee, V. Renard, S. Guerin, O. Faucher, B. Lavorel. Optical gratings induced by field-free alignment of molecules. Physical Review A : Atomic, molecular, and optical physics [1990-2015], 2007, 75, pp.013419. ⟨hal-00397076⟩