Effects of narrow-band pulse shaping on a resonant multilevel system

Phase and amplitude modulation of small frequency ranges within broadband femtosecond pulses reshape these pulses providing transients before, before and after, or after the main femtosecond pulse. The absorbed or phase-modulated frequencies appear as transients. We present experimental observations and calculations showing to what extent these transients can be used to drive population changes in the three-level 5s-5p-5d rubidium system in the perturbative limit. We also show computationally that these transients can assist to create complete inversion with nearly 98% population in the upper 5d state of rubidium at realistic intensities.