Laser-induced molecular alignment probed by a double-pulse experiment

The authors have studied the multielectron dissociative ionization of CO using a linearly polarized YAG laser delivering 1015 W cm-2 at 1064 nm, with a pulse duration of 30 ps. By firing two identical laser pulses, with crossed polarizations and a time delay of 800 ps, they show that an intense laser field forces all the molecules to align along its polarization vector. The molecular confinement increases with the dissociation threshold energies of the decay paths involved. Surprisingly enough, the different molecular decay paths observed with a 30 ps pulse release the same 'magic' kinetic energies as already observed with 100 fs, 600 fs and 2 ps pulse durations.