Enhanced Localized Surface Plasmonic Resonances in Dielectric Photonic Band-Gap Structures: Fabry-Perot Nanocavities & Photonic Crystal Slot Waveguides

We describe approaches to enhance localized surface plasmons by placing metallic nanoparticles into two different structures: (i) Fabry-Perot (F-P) resonant cavities, and (ii) Photonic crystal slot waveguides. Through synchronization of the plasmonic and resonant modes, electric field at the surface of the nanoparticles is enhanced by a factor of 4~20 compared with the nanoparticles in free space, depending on the device structure and coupling mechanism. We report key differences between the F-P enhancement and the slow-light enhancement to the plasmonic effect in details. This theoretical investigation reveals a new method to strengthen plasmonic resonances and suggests that the sensitivity of existing plasmonic sensors can be further improved if they are integrated with dielectric resonant photonic devices.