Observation of ultrafast photoinduced dynamics in strongly correlated organic materials

Complex photoinduced dynamics in organic charge transfer complexes, which have strong electron correlation and low-dimensional electronic systems, have been investigated using various ultrafast analytical techniques. A short-lived hidden photoinduced phase was determined from the transient reflectivity spectrum using a 120 fs pulse over a wide photon energy range from infrared to visible. The initial process of the photoinduced dynamics and its electronic coherence were revealed using a pulse compression technique down to 12 fs. The molecular and lattice structures were found to change in a different way from the electronic states, based on observations using two types of time-resolved vibrational spectroscopy and femtosecond electron diffraction. Time-resolved photoemission electron microscopy was developed for observing transient domain structures during photoinduced phase transitions.