Femtosecond Pulse Sequences Used for Optical Manipulation of Molecular Motion

TLDR

Timed femtosecond pulse sequences produced by pulse‑shaping techniques enhance optical control of elementary molecular motion. By timing femtosecond pulses to match lattice vibrations, the authors repeatedly drive selected crystal‑lattice modes, analogous to pushing a swing, thereby steering molecules along chosen paths. The technique amplifies selected vibrational modes while suppressing others, demonstrating the potential for broader manipulation of molecular and collective behavior.

Abstract

Optical control over elementary molecular motion is enhanced with timed sequences of femtosecond (10 -15 second) pulses produced by pulse-shaping techniques. Appropriately timed pulse sequences are used to repetitively drive selected vibrations of a crystal lattice, in a manner analogous to repetitively pushing a child on a swing with appropriate timing to build up a large oscillation amplitude. This process corresponds to repetitively "pushing" molecules along selected paths in the lattice. Amplification of selected vibrational modes and discrimination against other modes are demonstrated. Prospects for more extensive manipulation of molecular and collective behavior and structure are clearly indicated.