Mode-focusing in molecules by feedback-controlled shaping of femtosecond laser pulses.
The feasibility of mode-selective excitation with broadband femtosecond laser pulses is demonstrated for toluene in liquid phase. A learning-loop optimal control scheme was applied to a stimulated Raman excitation process. Modifications of the phase shape of one of the exciting pulses resulted in dramatic changes of the mode distribution reflected in coherent anti-Stokes Raman spectra. An evolutionary algorithm guided the coherent excitation process to a selective enhancement or suppression of one or more vibrational modes over the complete coherence lifetime spanning several picoseconds. New ways of spectral filtering as well as exciting possibilities of mode-selective studying of chemical reaction dynamics are indicated.
Konradi
J
J
School of Engineering and Science, International University Bremen, Campus Ring 1, D-28759 Bremen, Germany.
Singh
A K
AK
Materny
A
A
D005246:Feedback; D007834:Lasers; D012680:Sensitivity and Specificity; D013059:Spectrum Analysis, Raman / Q000379:methods; D013997:Time Factors; D014050:Toluene / Q000737:chemistry* / Q000528:radiation effects
D014050:Toluene