Time-Resolved Double Ionization with Few Cycle Laser Pulses

Ionization of ${\mathrm{D}}_2$ launches a vibrational wave packet on the ground state of $\mathrm{D}_2{}^{+}$. Removal of the second electron places a pair of ${\mathrm{D}}^{+}$ ions onto a Coulombic potential. Measuring the ${\mathrm{D}}^{+}$ kinetic energy determines the time delay between the first and the second ionization. Caught between a falling ionization and a rapidly rising intensity, the typical lifetime of the $\mathrm{D}_2{}^{+}$ intermediate is less than 5 fs when an intense 8.6 fs laser pulse is used. We simulate Coulomb explosion imaging of the ground state wave function of ${\mathrm{D}}_2$ by a 4 fs optical pulse and compare with our experimental observations.