Optical Response of a Subwavelength Grating Waveguide Loaded With a Plasmonic Nanoantenna

Single plasmonic-nanoparticle sensing holds a great promise in ultra-small analyte volume detection. Waveguide-loading is a simple way to achieve single nanoantenna interrogation in comparison to free-space configurations. Previously, we have reported the optical behaviour of dielectric waveguides loaded with simple and compound plasmonic-nanoantennae and the refractive index sensing performance of this setup[12]. Here, we extend this work by replacing dielectric waveguide with a SWG waveguide to improve the coupling efficiency. The numerical study shows that the coupling efficiency is doubled and sensitivity is improved considerably for refractive index sensing. This geometry promises on-chip applications like refractive index sensing and small footprint attenuators.