Experimental observation of revival structures in picosecond laser-induced alignment of I2.

We report the experimental observation of revival structures in the alignment of a ground-state rotational wave packet following nonresonant excitation of I2 molecules by an intense picosecond laser pulse. The revivals appear at characteristic time delays following the excitation by the pump laser pulse, and show a significant narrowing of the angular distribution during a few picoseconds. The interaction with the pump laser also leads to a steady-state alignment of the molecule, due to rotational pumping.