Preparation and monitoring of high-ground-state vibrational wavepackets byfemtosecond coherent anti-Stokes Raman scattering

Femtosecond time-delayed coherent anti-Stokes Raman scattering is presented not only as a tool for monitoring but also as a viable method for the prep aration of vibrational wavepackets with very high quantum numbers in the gr ound electronic state of molecules. We experimentally demonstrate a particu larly useful approach of using two separate time delays between the pulses for preparing vibrational wavepackets as high as v"=38 [DeltaE(v)=7000 cm(- 1)] in bulk gas- phase molecular iodine. By means of an ultrashort laser pu lse, we prepare a wavepacket in an electronic excited state, optimize the f requency and timing of a second pulse to efficiently generate the targeted ground-state vibrational wavepacket, and monitor the wavepacket by coherent scattering from a third pulse. The method is further used to probe interfe rence effects in femtosecond four-wave-mixing signals generated by molecula r wavepackets. (C) 2001 American Institute of Physics.