During the last decade the use of laser radiation has grown far beyond its traditional role as a convenient, bright and spectrally narrow source of light. In particular, the coherence properties of the radiation have been put to use for very detailed and fine work in spectroscopy, collision dynamics and the manipulation of both the internal structure and the center of mass motion of atoms and molecules.
These are the key words describing the work program of the research network “Laser Controlled Dynamics of Molecular Processes and Applications (ERB-CHR-XTC-94-0603),” established by the European Union under the program “Human Capital and Mobility (HCM)” with the intent of sending young researchers (postdocs and students) across national borders within the European Union.
During the past four years research teams in Germany (Göttingen and Kaiserslautern), France (Paris and Dijon), The Netherlands (Nijmegen), and Italy (Trento) cooperated on a wide range of topics related to the application of lasers in spectroscopy, collision dynamics and the manipulation of atoms and molecules by coherent radiation. The series of annual workshops ended with a final meeting of participants and invited scientists for a workshop, held in Kaiserslautern September 23 – 25, 1998. The lectures during that meeting provided an overview of the results achieved by network partners and indicated possible future directions for individual or collaborative work. The scientific program of that workshop is the platform for this Optics Express Focus Issue on “Laser Controlled Dynamics”.
Examples of very promising new spectroscopic tools or techniques which have been introduced as part of the network program (and which have provided interesting new results) are the use of the packets of chirped pulses of radiation from the free-electron laser FELIX to study the excitation dynamics of C60 produced by hundreds of photons [see the paper by von Helden et al.]. The study of nonlinear optical processes involving atoms or clusters near surfaces [see the paper by Bordo and Rubahn], or the formation and resolution of pronounced laser-induced continuum structure (LICS) in He* or the development of novel element for atom-optics [see the work of Theuer et al.]. The Dijon group examined theoretical techniques which permit analysis and modeling of novel coherent pulse effects [see Guérin et al.].The Paris group worked succesfully on pushing the limits in using extremely slow molecules to implement Ramsey-fringe schemes for very high resolution spectroscopy [see Klein et al.], while the Trento group explored the effect of laser-controlled vibrational excitation of molecules on the dynamics of their interaction with surfaces [see van Opbergen et al.].
The invited speakers from outside the network emphasized promising new directions. M. Shapiro reported on new theoretical work paving the way for laser-induced recombination to form cold molecules [see Vardi et al.]. M. Fleischhauer [see Fleischhauer] and G. Djotyan [see Djotyan et al.] explored new schemes to create coherent superpositions of quantum states in a controlled manner, a hot topic in the rapidly expanding field of quantum information systems, while H.Giessen [see Giessen et al.] showed that coherent phenomena, similar to those known in the gas phase can also be observed in semiconductors.
In summary, the workshop program - and this Focus Issue - provides a comprehensive view of the rich variety of new phenomena and techniques which makes the field of laser controlled dynamics a fascinating one - for the time being and for the future.
We thank Bruce W. Shore for his contribution to the HCM workshop and in particular for his collegial oversight and very helpful editorial suggestions with regard to this Focus Issue.