Using a broadband femtosecond laser and a simple optical setup, we demonstrate narrow-bandwidth-tunable excitation of vibrational modes in CCl<sub>4</sub> and CHBr<sub>3</sub> liquids. The resolution obtained is 80 times higher than the laser bandwidth. A pair of time-shifted, linearly chirped pulses is created by use of a high-order dispersion-compensated prism–interferometer setup. We use this pulse pair to selectively excite Raman-active transitions. Our setup represents a significant simplification with improved resolution, of previous approaches to the use of ultrashort pulses for chemically selective spectroscopy.
© 2003 Optical Society of America
(190.0190) Nonlinear optics : Nonlinear optics
(190.4380) Nonlinear optics : Nonlinear optics, four-wave mixing
(300.0300) Spectroscopy : Spectroscopy
(320.0320) Ultrafast optics : Ultrafast optics
E. Gershgoren, R. A. Bartels, J. T. Fourkas, *R. Tobey, M. M. Murnane, and H. C. Kapteyn, "Simplified setup for high-resolution spectroscopy that uses ultrashort pulses," Opt. Lett. 28, 361-363 (2003)