Fs photo-isomerization in bacteriorhodopsin by few-cycle pulses

Takayoshi Kobayashi*, Atsushi Yabushita

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


We have build up non-collinear optical parametric amplifier (NOPA) laser system with adaptive pulse tailoring, which enables to generate sub-4-fs laser pulses. Using the ultrashort laser pulses generated by NOPA, we have performed pump-probe measurement of bacteriorhodopsin (bR) using ultrashort pulses, which can observe real-time frequencies of molecular vibrations. Both of the spectra of pump and probe pulses are nearly the same and cover a spectral range from 500 to 710 nm with a nearly constant phase. The time-gated Fourier transform of the measured absorbance change trace revealed that the frequency of the C{double bond, long}C stretching mode was modulated along with the torsion motion around C13{double bond, long}C14 during the photoisomerization of bR. It shows the bond length of C13{double bond, long}C14 is modulated on the deformation around C13{double bond, long}C14 during the photoisomerization. The hydrogen-out-of-plane (HOOP) mode and the in-plane C{double bond, long}C-H bending mode coupled with C-C stretching mode are found to be intermixed with each other in the same period of the torsion motion. It also shows us the real-time conformation change of the molecule, which makes both of the modes indistinguishable.

Original languageEnglish
Pages (from-to)1038-1042
Number of pages5
JournalJournal of Luminescence
Issue number5-6
StatePublished - 1 May 2008


  • Difference absorption spectrum
  • Pump-probe spectroscopy
  • Real-time spectroscopy
  • Ultrafast


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