Regensburg 1998 – wissenschaftliches Programm
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O: Oberflächenphysik
O 18: Hauptvortrag
O 18.1: Hauptvortrag
Dienstag, 24. März 1998, 15:15–15:45, H36
Free electron laser for infrared SEW surface characterization of conducting and dielectric solids and nm-films on them — •G.N. Zhizhin1, E.V. Alieva1, L.A. Kuzik1, A.F.G. van der Meer2, and M.J. van der Wiel2 — 1Institute of Spectroscopy, Russian Academy of Sciences, Troitsk, Moscow oblast, 142092 Russia — 2FOM-Institute for Plasmaphysics, MN Nieuwegein, 3439 Netherlands
The nature and transformations of surface electromagnetic waves (SEW) on metals (surface plasmons) and dielectrics (phonon-polaritons) are discussed. The set of problems that can be solved by new highly sensetive method of investigation of surfaces and very thin layers on solids - the surface electromagnetic waves spectroscopy- are presented. The field of application ofthis method was considerably extended with the use of a high-intensity FELIX free-electron laser, which can be tuned within the broad spectral range. Interferometric SEW experiments provide the possibility for direct determination of the real and imaginary parts of dielctric constants at the frequencies inside the FEL tunability range, avoiding the Kramers-Kronig integral transformation commonly used for reflection spectra. The applications are demonstrated by the examplesof the IR spectra Langmuire-Blodgett monomolecular films on metals,of a metal oxide film, and of polymer films of nanometer thicknesses on metals, exposing the effects of chain conformation changes induced by solid surface. In the middle and far IR the "reststrahlen" range optical constants of CaF2, BaF2, MgO, LiNbO3, KTiOPO4 single crystals were determined as well as the new polymer CARILON thin films’. The nonlinear spectroscopic applications of the SEW-FL technique for studies of second harmonic generation on crystal surfaces in the regime of counterpropagating surface electromagnetic waves are discribed.