A tunable, ultrafast
system generating mid-IR
radiation is described and its output characterized. The system is designed to explore vibrational dynamics in the condensed phase in a direct, two-pulse, time-resolved manner, using Raman spectroscopy as the probe. To produce vibrational resolution, probe pulses are spectrally narrowed by use of a long doubling crystal. Frequency-resolved optical gating is used to evaluate beam characteristics. An effective method for determining the temporal overlap of the pump and probe pulses for a one-color,
configuration is illustrated. Representative results from studies of heme and para-nitroaniline vibrational dynamics illustrate the effectiveness of the visible pump–visible probe portion of the system in illuminating fast structure and energy dynamics.
© 2006 Optical Society of America