Picosecond Time-Resolved Raman/Coherent-Raman Spectroscopy Using the “Pico-Pump and Quasi-CW Probe” Method with a Streak Camera
A Picosecond time-resolved spontaneous Raman measuring system using a streak camera was constructed. Nanosecond probing laser pulses were used with picosecond UV pumping. Raman scattering at each delay time was time-resolved and detected by a streak camera. Two dimensional (the time and the frequency domain) simultaneous detection of Raman scattering has been carried out. Time-resolved Raman spectra of benzophenone at delay times ranging from −1.25 ns to 1.5 ns were obtained with one single measurement. A picosecond time-resolved multiplex CARS measuring system based on the same principle was also constructed. Nanosecond narrow band laser pulses and broad band dye laser pulses were used as CARS probing ω1 and ω2, respectively, with the picosecond UV pumping pulses. The cis-trans photoisomerization dynamics of all-trans and 9-cis retinal was investigated. It was clarified that the conformational change from the 9-cis form to the all-trans takes about 880 ps in the triplet manifold.
KeywordsRaman Scattering Raman Band Streak Camera Picosecond Laser Pulse Regenerative Amplifier
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