On the Resolution Limit of Femtosecond Stimulated Raman Spectroscopy: Modelling Fifth‐Order Signals with Overlapping Pulses |
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| Authors: | Giuseppe Fumero Giovanni Batignani Dr. Konstantin E. Dorfman Prof. Shaul Mukamel Prof. Tullio Scopigno |
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| Affiliation: | 1. Dipartimento di Fisica, Universitá di Roma “La Sapienza”, Roma, Italy;2. Dipartimento di Scienze Fisiche e Chimiche, Universitá degli Studi, L'Aquila, Italy;3. Department of Chemistry, University of California, California, Irvine, USA;4. Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, Roma, Italy |
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| Abstract: | Femtosecond stimulated Raman scattering (FSRS) spectroscopy is a powerful pump–probe technique that can track electronic and vibrational dynamics with high spectral and temporal resolution. The investigation of extremely short‐lived species, however, implies deciphering complex signals and is ultimately hampered by unwanted nonlinear effects once the time resolution limit is approached and the pulses overlap temporally. Using the loop diagrams formalism we calculate the fifth‐order response of a model system and address the limiting case where the relevant dynamics timescale is comparable to the pump–pulse duration and, consequently, the pump and the probe overlap temporally. We find that in this regime, additional diagrams that do not contribute for temporally well separated pulses need to be taken into account, giving rise to new time‐dependent features, even in the absence of photoinduced dynamics and for negative delays. |
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| Keywords: | femtochemistry nonlinear optics pump– probe spectroscopy Raman spectroscopy time-resolved spectroscopy |
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