Phase Sensitive Pump-Probe Spectroscopy Using a Michelson-Type Interferometer

Time-resolved phase sensitive pump-probe spectroscopy using a Michelson-type interferometer has been carried out. In this experiment, we obtain information on the time-resolved amplitude and phase of probe pulses by measuring cross-correlations between probe pulses and reference pulses. This method was demonstrated in an experiment on dye molecules, hexamethylindotricarbocyanine iodide, in ethylene glycol at room temperature. The experimental results indicated the time evolution of the phase and the increase in peak velocity of the probe pulse. These phenomena can be explained by phase velocity change and group velocity change due to the pump pulse. A simulation based on a two-level Bloch model for the dye molecules reproduced the experimental results quite well.