DESIGN OF CHEMICAL SENSORS BASED ON SURFACE ENHANCED RAMAN SCATTERING

Abstract

When light waves, with a specific wavelength, are incident on a metal-dielectric interface or on a nanoparticle, surface plasmons, localized surface plasmons or coupled plasmons are excited and lead to intensity enhancement. This phenomenon of light enhancement can be achieved by fabricating nanostructures with specific geometries and parameters. When these nanostructures are engineered appropriately, they result into light intensity enhancement of the order of tens of thousands. The phenomenon of electric field enhancement by using nanostructure with sharp edges, called lightning rod effect, can be exploited to further intensify the localized surface plasmons. For further enhancement of electric field intensity the possibility of enclosing these nanostructures within nano-line grating walls was explored. Variation of different parameters of these structures like orientation, gap and structural dimensions is explored for their influence on electromagnetic field enhancement. By optimizing these nanostructures, this work aims to propose an optimal nanostructure with high electromagnetic enhancement, for sensing chemical agents in trace quantities.