MANIPULATING EXTERNAL DEGREES OF FREEDOM WITH INTENSE LIGHT - LASER FOCUSING AND TRAPPING OF MOLECULES

The possibility of focusing and trapping molecules in the intensity gr adient of a moderately intense laser field is shown. A fully quantum-m echanical and a hybrid quantum-classical model are developed and both the case of a near-resonance and that of a far-off-resonance field are studied numerically and analytically. Molecular focusing is obtained when the ratio between the kinetic energy and the field-matter interac tion exceeds unity (but remains small). In this energy regime the lase r beam serves as a lens for a beam of molecules. The properties of the ''molecular lens'' are analysed and the experimental conditions requi red to focus molecules are examined. We propose the application of las er focusing to nanoscale deposition onto, and etching of a substrate a nd describe a possible setup to that end. Molecular trapping is obtain ed as the strong interaction limit of a general ''molecular optics'' s cheme. (C) 1997 American Institute of Physics.