Photon echo 2D electronic spectroscopy (2DES) is a third order time-resolved optical spectroscopy technique, where sample interacts with three noncollinear femtosecond laser pulses, and then emits a signal carrying information about the properties of the sample. Measured 2D spectra are spread on so called excitation and detection frequencies and show correlations between different optical transitions in the system under investigation. Following temporal evolution of the 2D spectra enables direct measurement of electronic couplings and energy transfer pathways, and also allows for observation of coherence dynamics. These properties make 2DES the method of choice when exploring the light-triggered processes in complex systems.
We employ 2DES for studying photosynthetic chromophore-protein complexes, artificial molecules and nanostructures. We aim at unravelling a complete picture of photophysical and photochemical processes in these systems. Of particular interest is energy and electron transfer in photosynthetic light-harvesting complexes and reaction centers, which demonstrate remarkable efficiency and robustness.