Investigations of amplitude and phase excitation profiles in femtosecond coherence spectroscopy

By Anand Kumar, F. Rosca, A. Widom, P. Champion. 2000

162 citations recorded by the source corpus.

We present an effective linear response approach to pump–probe femtosecond coherence spectroscopy in the well-separated pulse limit. The treatment presented here is based on a displaced and squeezed state representation for the nonstationary states induced by an ultrashort pump laser pulse or a chemical reaction. The subsequent response of the system to a delayed probe pulse is modeled using closed form nonstationary linear response functions, valid for a multimode vibronically coupled system at arbitrary temperature. When pump–probe signals are simulated using the linear response functions, with the mean nuclear positions and momenta obtained from a rigorous moment analysis of the pump induced (doorway) state, the signals are found to be in excellent agreement with the conventional third-order response approach. The key advantages offered by the moment analysis-based linear response approach include a clear physical interpretation of the amplitude and phase of oscillatory pump–probe signals, a dramatic i...

Subfields: Atomic and Molecular Physics, and Optics, Cellular and Molecular Neuroscience

View Paper: https://www.semanticscholar.org/paper/e1f45abfadb14982374bf2ee91f9fd9f4adbf01a