Title: THz Induced Field-Free Orientation of Rotationally Excited Molecules

K. Egodapitiya, Sha Li, and R.R. Jones

University of Virginia, Charlottesville, VA 22904, USA

Abstract:

We have used picosecond THz pulses to induce transient field-free orientation of OCS molecules. Coherent optical Raman excitation prepares the molecules in rotational superposition states prior to THz irradiation, substantially enhancing the degree of orientation. The time-dependent alignment and orientation are characterized via Coulomb explosion in an intense probe laser. The degree of orientation is an order of magnitude larger than previously observed following THz irradiation, and is achieved with a significantly smaller THz field. The orientation level is comparable to that generated using two-color laser fields, but is obtained with negligible target ionization.

Status: Published Physical Review Letters 112, 103002 (2014).