Development of a Transient Absorption Spectrometer to Analyze Molecular Dynamics

Ultrafast dynamics contribute to photo-physical processes such as photosynthesis, where
energy transfer between light absorbing molecules takes place on the timescale of hundreds of
femtoseconds to hundreds of picoseconds. We present progress on the development of a
transient absorption spectrometer to characterize ultrafast dynamics in molecules and light
harvesting materials. The spectrometer consists of a pump-probe geometry. The delay is created by using an optical stage and the resolution of the stage was tested with a Michelson
Interferometer. We obtained a step size accuracy below 2 fs. The instrument is nearing
completion to test laser dyes as model systems to characterize the structure of normal mode
oscillations in the nonlinear spectra.