Raman spectroscopy of sol-gel ultrathin films enhanced by surface plasmon polaritons

We present experimental results of a Kretschmann-prism coupler method used in Raman scattering experiments with ultrathin (few nanometers) TiO2 sol-gel films deposited on a metallic silver layer characterized by surface plasmon resonance (SPR) experiments. In this article, we describe a new optical device as an application of SPR properties and coupled with a micro-Raman scattering setup. The enhancement factor (150) of the Raman intensity in comparison to the classical way allows us to determine the critical thin films structure. Optical results are then discussed and compared to transmission electron microscopy. (C) 2000 American Institute of Physics. [S0021-8979(00)07619-2].