| Abstract
| - Dispersed multipump−probe (PPP) spectroscopy was used to explore the role of saturation, annihilation, andstructured pulses in recent coherent control experiments on the light-harvesting 2 complex from Rhodopseudomonas acidophila (Herek et al. Nature2002, 417, 533). We discuss the complimentary aspects between thePPP technique and coherent control studies, in particular the ability to dissect complicated pulse structuresand the utility in exploring incoherent mechanisms. With the aid of a simple multistate model involving onlypopulation dynamics, we illustrate how the optimized structured pulses may be explained in terms of aninterplay between excited-state populations, saturation, and annihilation. Furthermore, we discuss theexperimental conditions that are required for incoherent effects to contribute to control experimental signals,with particular emphasis on pulse intensities, and show that the optimization of a ratio of conservative signals(i.e., not modulated by external dynamics) is required to exclude saturation effects from coherent controlstudies.
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