OPTICAL CONTROL OVER 2-DIMENSIONAL LATTICE VIBRATIONAL TRAJECTORIES IN CRYSTALLINE QUARTZ

Control over the trajectory of two-dimensional vibrational motion is d emonstrated for a degenerate E-symmetry optic phonon mode in crystalli ne quartz. Pairs of ultrashort optical pulses of different polarizatio ns are used to impart momentum along orthogonal directions of the dege nerate mode through impulsive stimulated Raman scattering. Variation o f the temporal separation of the two excitation pulses permits various Linear, elliptical, or circular trajectories to be selected. More com plex two-dimensional trajectories are also possible if arbitrarily sha ped excitation waveforms are used. (C) 1998 American Institute of Phys ics.