Using of two pump pulses in the study of the ultrafast optical Kerr effect in demethilformamide liquid

摘要

We demonstrate experimentally the laser control of the nonstationary anisotropy of polarizability in a pure liquid of demethilformamide (CH_3)_2NCOH at room temperature. The experiment is based on the nonresonant medium excitation by a sequence of two linear polarized laser pulses with the duration of 60 fs. The state of medium is probed by the third weak laser pulse with the registration of the ultrafast optical Kerr effect. We obtained that by using two parameters (the delay between the pump pulses and the angle between the directions of the linear polarization of two pump pulses) the molecular orientational anisotropy in liquid is controlled in the subpicosecond time scale.