Application of a two-color free-electron laser to condensed-matter molecular dynamics

Abstract

The possible applications of a free-electron laser (FEL), which would be modified to produce two synchronized, independently tunable picosecond pulses, are considered. At least one of the pulses would be available in the vibrational infrared region. Such an instrument would be more useful in the area of condensed-matter molecular dynamics than the conventional one-color FEL. We review briefly the dynamical processes of greatest interest in complicated, condensed-matter molecular systems. We discuss how a one-color and a two-color FEL can be used for experimental measurements of these processes and the advantages that a two-color system would have over existing technologies. We then provide a model calculation to determine the feasibility of these experimental measurements. This calculation is based on the anlysis of two-color FEL’s by Schwettman and Smith [J. Opt. Soc. Am. B6, 973 (1989)]. Finally we examine the most promising applications of a two-color FEL and propose several specific experiments. The applications that are discussed include vibrational relaxation in molecular systems, dynamics of surfaces, photobiology and biophysics, and coherent optical measurements of intrinsically disordered materials.