Time-Resolved Infrared Spectroscopy at DFELL

(WE-Wrk-2-02)

M. Shane Hutson, Richard A. Palmer, Vladimir Litvinenko and Glenn Edwards  

Duke University

A novel two-color beamline has been constructed at the Duke Free Electron Laser Lab to perform time-resolved infrared spectroscopy in a pump-probe scheme. The pump pulse beam is supplied by the output of the OK-4 UV FEL operating on the Duke storage ring. It is capable of lasing throughout the visible spectrum and deep into the ultraviolet, to wavelengths as short as 193 nm. The broadband, infrared probe pulses are generated as synchrotron radiation in the subsequent bending magnet. As the same bunch of electrons emits both pulses, the timing between the pump and probe is jitter-free. The attainable time resolution is thus limited only by the pulse-widths ($\tilde{\hspace{0.4em}}$30 ps). The capability to excite systems with tunable ultraviolet radiation and then probe the relaxation processes in the infrared with time resolution below 100 ps is unique, and opens doors to the study of photochemical and photobiological systems not previously accessible to time-resolved infrared spectroscopy.