"Galileo Galilei" Colloquium (July 6th 2004)

 "Controlling External Molecular Modes with Intense Light"


Prof. Tamar Seideman
Northwestern University, Evanston, IL (U.S.)

Department of Mathematics "L. Tonelli"
Via F. Buonarroti, 2
Aula Magna Faedo  - at 15:30

Moderately intense laser fields can be used to excite rotationally broad, coherent superposition states with fascinating properties that may also be potentially useful. We illustrate the possibilities of forcing the three axes of an arbitrary polyatomic molecule to align along given three axes fixed in space, of preserving the field induced alignment after turn-off of the laser pulse, of forming superposition states that are perfectly aligned and fully isotropic periodically in time, and of focusing, collimating, steering, dispersing and reflecting molecular beams with light. Potential applications include a new opportunity for quantum storage, control of charge separation and charge recombination reactions, separation of racemic mixtures of chiral molecules into pure enantiomers, generation of high harmonics and of ultrashort (attosecond) pulses, enhancement of the sensitivity of time-resolved probes of polyatomic dynamics, and nanoscale processing of surfaces.

In the talk I will discuss the qualitative physics underlying intense laser alignment and molecular optics, briefly sketch our theory, outline the results of ongoing research and mention several of our dreams and plans in this area.