Non-ideal two-dimensional electronic spectroscopy: Theory for a transparent nonlinear system

Abstract

The necessary requirement for an ideal two-dimensional electronic spectroscopy experiment is utilization of ultrashort optical pulses with rectangular spectra for pulse envelopes, while the system transitions fall within the optical pulse window. In this case, the obtained spectra shows clear resonances of the sample response function and various quantum transitions are mapped onto the two-dimensional spectra without distortions. Such conditions, however, are not realistic: first, the pulses never have such spectral profile; second, there may be many transitions that are away from the optical window. In this paper, we present general practical expressions for simulating two-dimensional electronic spectroscopy measurements with specific pulse spectral profiles, and we demonstrate that the off-resonant transitions may have large contributions to the spectra especially at short delay times, when pulse overlaps are significant.