5. Fs Stimulated Raman Spectroscopy Spectrometer

Technique 

Three pulses are involved. An actinic pump pulse excites the molecule to trigger a photochemical reaction. The vibrational transitions of the molecule, represented by its Raman spectrum, is then probed at various time delays by two simultaneous pulses, a narrowband Raman pump pulse and a broadband probe pulse. The time resolution is limited only by cross correlation of the actinic pump and Raman probe pulses, which is 100 fs.

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Units

Three independent laser pulses, one detection scheme

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Instrument type

Homemade

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Complexity level

High

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Applications

Experimental tool for investigating ultrafast structural and vibrational dynamics of systems in excited state on a time scale 0-4 ns.  The method is extremely sensitive to changes in nuclear coordinates as small as 0.01 A and allows watching a chemical or biological reaction in real time.