Enhanced waveguide Raman spectroscopy with thin films. Plenary lecture

Abstract

A sensitive Raman analytical technique for the study of thin films, surfaces and interfaces is demonstrated. Waveguide Raman spectroscopy (WRS) provides for a non-destructive evaluation of thin films in the micrometre and submicrometre regime. High intensity propagating waves have been used to sample molecules within waveguides, and interfacial species have been sampled by the evanescent portions of the optical field which tail into the substrate and superstrate regions of the waveguide structure. Variations of the simple waveguide experiment have been explored in surface and interface studies. Both resonance Raman spectroscopy and, for the first time, surface-enhanced resonance Raman spectroscopy (SERRS) have been used in combination with the waveguide technique, providing further increases in sensitivity. Experiments performed include waveguide resonance Raman spectroscopy of chromophores (beta-carotene on a polymer surface; tetraphenylporphine sulfonate at a polymer/glass interface; poly(vinyl chloride)(PVC) degradation products incorporated within a PVC thin film, and a novel combination of SERRS with WRS to detect tris(2,2-bypyridine)ruthenium(II) chloride hexahydrate incorporated within a polymer thin film.