Estudio de los mecanismos con plasmones superficiales en interfaces de peliculas para el mejoramiento de la espectroscopia Raman (SERS)

Abstract

The objective of the present work is to find possible mechanisms for the enhancement of Raman spectroscopy (SERS) through surface plasmons (SP) for the experimental Kretschman configuration. In the first step, a theoretical analysis of the presence of surface plasmons in the metal/dielectric interface was made based on the classical electromagnetic theory, providing minimum optical conditions to generate them; Subsequently, the excitation of (SP) in a stratified medium (prism, metal film and dielectric) was examined using the functions of reflectance and transmittance. It is shown that in the resonance condition (SPR) the intensity of the electric field (Ong et al., 2006) in the metal/dielectric interface increases considerably with respect to the incident intensity inside the prism when using metallic films of silver (Ag) and gold (au). Finally, Raman spectroscopy was studied, obtaining that the intensity of Raman scattering (Long, 2002) depends directly proportional to the amplitude of the oscillating dipoles, in turn these depend on the polarization tensor of the molecules (dielectric medium) and the electric field incident on them, which allowed deducing that the intensity Raman is increased if the intensity of the incident field is increased, and definitely this happens for SPR obtaining SERS. It is also important to highlight that the present work in favor of pedagogy and didactic was elaborated demonstrating in general each mathematical procedure with its physical analysis, deepens each one of the fundamental concepts, and this, with the so that future readers, both inexperienced and experts on the subject, obtain a compact theory, which allows them to lay foundations in the investigation of surface plasmons (SP) and their possible applications and theoretical developments.