Coupling of plasmonic and optical cavity modes in quasi-three-dimensional plasmonic crystals.

The field of plasmonics has emerged as an interesting area for fundamental studies, with important application possibilities in miniaturized photonic components. Plasmonic crystals are of particular relevance because of large field enhancements and extraordinary transmission that arise from plasmonic interactions between periodic arrays of metallic elements. Here we report methods to enhance and modify the plasmonic resonances in such structures by strongly coupling them to optical modes of Fabry-Perot type cavities. First, we illustrate a type of plasmonic, narrow-band (~15 nm), high-contrast (>20 dB) absorber and an opto-fluidic modulator based on this component. Second, we use optimized samples as substrates to achieve strong amplification (>350%) and modulation (>4×) of surface-enhanced Raman scattering from surface-bound monolayers. Cavity-coupling strategies appear to be useful not only in these two examples, but also in applications of plasmonics for optoelectronics, photovoltaics and related technologies.