Figure 1

Alignment factor vs time after excitation by a laser pulse with (a) $P_s=-10$ and (b) $P_s=10$. Solid curves present quantum results. Dashed curves are calculated classically (a) for positive time and (b) for negative time (shifted by ${\tau }_{\mathit{rev}}$). Strong antialignment is seen in both cases.Reuse & Permissions

Figure 2

Classically optimized orientation factor (solid curves) and delay between pulses (dashed curves). The laser pulse is fired before the half-cycle pulse.Reuse & Permissions

Figure 3

Classically optimized orientation factor (solid curve) and delay between pulses (dashed curve). The laser pulse is fired after the half-cycle pulse.Reuse & Permissions

Figure 4

Quantum-mechanical optimized results. Left column, (a) and (b), corresponds to the laser pulse fired before the HCP; right column, (c) and (d), corresponds to the reversed order of pulses. Upper panels (a) and (c) display the optimal strength of the antialigning pulse (solid lines) and delay between pulses (dashed lines) as a function of the HCP strength. Lower panels (b) and (d) present the highest value of the postpulse orientation factor vs the strength of the HCP. Negative delay times correspond to the second pulse applied before one full revival (as explained in the text).Reuse & Permissions