With the method of self-diffraction of incoherent light, molecular vibrations were observed in real time in various dye molecules pumped near the absorption edge. In Rhodamine 560, 35-fsec oscillations in the signal were measured, which corresponds to a vibrational frequency of 1000 cm−1. Simultaneously, this technique can be used to deduce the ultrafast dephasing times in the molecular vibrational quasi-continuum. Dephasing times of 20 and 150 fsec were observed in Rhodamine 590 and Rhodamine 560, respectively.
© 1990 Optical Society of America
Original Manuscript: December 26, 1989
Manuscript Accepted: February 22, 1990
Published: May 1, 1990
Z. Q. Huang, Y. J. Xie, G. L. Huang, and H. S. Kwok, "Observation of molecular vibrations in the time domain with incoherent laser pulses," Opt. Lett. 15, 501-503 (1990)