SPECTROSCOPIC TECHNIQUES USING SYNCHROTRON-RADIATION AND FREE-ELECTRON AND CONVENTIONAL LASERS

Considerable progress in the investigation of the electronic and vibra tional properties of atoms, molecules, materials, surfaces and interfa ces has been achieved by combining different photon sources of complem entary characteristics. In this paper some experimental results obtain ed recently at LURE by using two synchronized sources, such as the IR free-electron laser (FEL) CLIO, the VUV storage ring FEL, synchrotron radiation and table lasers, are presented. Using CLIO synchronized wit h a YAG laser allows the investigation of the vibrational properties o f adsorbed species by the non-linear optical technique of visible-IR s um (difference) frequency generation, as shown for the adsorption of h ydrogen on platinum in the electrochemical environment. The second res ult reported here relates to the study of the intersubband stimulated emission in GaAs/GaAlAs quantum wells by pump-probe experiments using the two-colour configuration of CLIO. The combination of a mode-locked Ar+ laser and synchrotron radiation has been used for investigations in a pump-probe arrangement of the ionization of Xe atoms via the reso nant state Xe 5p(5)5d [3/2](1). The final example is a time-resolved core-level spectroscopy study of photoexcited Si(111) 2 x 1 surfaces b y using a combination of the naturally synchronized UV storage ring la ser and synchrotron radiation.