Simultaneous control of time-dependent population transfer dynamics and wave-packet quantum interferences inLi2by shaped ultrafast pulses

Abstract

Ultrafast pulse shapes are used to control simultaneously the optimal population transfer coefficients and rotational wave-packet quantum interferences in the $E{}^{1}{\ensuremath{\Sigma}}_{g}^{+}$ state of ${\mathrm{Li}}_{2}$ $({\ensuremath{\nu}}_{E}=9,$ ${J}_{E}=27$ and 29). By dividing the spectral bandwidth of the ultrafast pulses into multiple ``control domains'' centered on each resonant wavelength, the population transfer coefficients can be manipulated independently of the wave-packet interferences to maximize the ${\mathrm{Li}}_{2}$ photoionization yield at arbitrary short pump-probe time delays. To investigate the population transfer coefficients with and without wave-packet interferences, respectively, the pump polarization is set to be either parallel to or at the magic angle (\ensuremath{\sim}55\ifmmode^\circ\else\textdegree\fi{}) relative to the probe polarization. A comparison is made between phases that are symmetric and antisymmetric about the resonances. The effects of resonant and nonresonant frequencies are separately established and quantified. It is estimated that up to 90% of the possible nonresonant Rabi oscillations can be brought into phase simultaneously for each rovibrational state in the wave packet, while at the same time a constant phase offset added to one of the control domains establishes the phase of the wave-packet interference.