2D Strong-Field Spectroscopy to Elucidate Impulsive and Adiabatic Ultrafast Electronic Control Schemes in Molecules

Abstract We present a multidimensional spectroscopy approach based on strong-field coherent electronic excitation to elucidate intramolecular dynamics and unveil control mechanisms. Traditional 2D spectroscopy generally relies on weak-field interactions and the well-known control mechanism of spectral interference (SI) with its characteristic I n -scaling of transition probabilities (I, laser intensity; n, photonic order). For non-perturbative strong-field interactions, completely different scenarios become relevant. Especially, electronic coherences play a significant role to control the population dynamics and the bidirectional Stark shifts. To that end, we study the potassium dimer prototype both experimentally and with the help of quantum dynamics simulations. We employ two distinct types of shaped femtosecond laser pulses that induce either impulsive or adiabatic excitation of atoms and molecules – both directly related to coherent strong-field interaction.