The role of microscopic and macroscopic coherence in laser control Original Research Article

In this article, we discuss microscopic and macroscopic coherences resulting from multiple pulse excitation of molecular samples. The wave packet formalism is applied to describe the interference of wave packets within a single molecule (microscopic coherence) and the macroscopic interference between the polarizations resulting from optical responses of a single molecule or from different molecules (macroscopic coherence). Experimental virtual echo and stimulated photon echo measurements with noncollinear, degenerate femtosecond pulses are presented where both of these coherences are shown to control the observed dynamics. Theoretical simulations of the rovibronic dynamics observed experimentally on iodine vapor are presented. The role of these coherences in laser control of quantum dynamics is discussed.