Investigation of metallic surface layers on metals by surface plasmon ATR spectroscopy

Abstract

2014 Les résultats optiques obtenus par une technique de réflexion totale, atténuée avec excitation d'ondes de plasma de surface sur des films très minces de Ag, sur des surfaces de Al, sont analysés dans le voisinage de la fréquence de plasma effective de l'Ag. On montre qu'il est nécessaire de tenir compte des effets non locaux (ondes de plasma longitudinales), et que la constante diélectrique complexe des films adsorbés est alors analogue à celle de l'Ag massif.Abstract. 2014 The optical properties of very thin Ag layers on Al surfaces were investigated in the vicinity of the Ag effective plasma frequency, by attenuated total reflection with surface plasma wave excitation. The complex dielectric constant of the adsorbed layers is found to be similar to that of bulk Ag provided non-local effects (longitudinal plasma waves) are taken into account. LE JOURNAL DE PHYSIQUE -LETTRES

The influence of plasma waves on the dispersion of surface plasmons : experimental evidence

“…The ATR experiments performed in a wide spectral range between 1.9 and 5 eV in Otto-geometry are reported in section 3. Around the effective plasma frequency of Ag (3.8 eV) the dispersion curve is characterized by a « back-bending » detected earlier by other authors [8,9] in Kretschmann-geometry.…”

“…The local treatment of the substrate as used in [9] has an impact on the PW propagation in the Ag-layer via the matching conditions at the Ag/Al-interface.…”

“…To solve this problem we have designed a thin film stratified electrode [6]. It consists of an optically thick Al-film as an SP-active metal up to the UV ( hw p -15 ev ) covered by a thin Ag-coating (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15) nm) to realize an electrochemically well defined contact to the electrolyte. We have applied this thin film electrode to study electrochemically induced surface roughness by the SP-technique [7].…”

Plasmonic enhancement of spatial dispersion effects in prism coupler experiments

“…Here we propose to use the classical prism-coupler configuration 10,34 to excite high wavevector plasmonic modes, in order to enhance the effects of spatial dispersion alone. We predict, relying on the hydrodynamic model and accurate material parameters, that the impact of spatial dispersion will be two orders of magnitude larger than what can be reached with simple surface plasmons.…”