Split Square Ring Resonator with Plasmonic MIM Waveguide for Sensing Application

Plasmonic chemical and biological sensors have many advantages such as compact sizes and extremely high sensitivity. Biosensors based on plasmonic waveguides and resonators are one of the most attractive candidates for industrial applications of nanotechnology. A Metal-Insulator-Metal (MIM) waveguide structure consisting of Split Square Ring Resonator (SSRR) was proposed and numerically investigated by using the Finite Element Method (FEM). After a detailed analysis of the transmission characteristics and magnetic field strength of the structure, the structure can generate two Lorentzian sharp resonances where it was found that resonance wavelength and transmittance can be achieved by adjusting the width of the split. In addition, after optimizing the geometric parameters, the refractive index sensing sensitivity (S) and figure of merit (FOM) of the structure can be optimal, which are \(1320\,nm/RIU\) and \(\mathrm{50,6 }\,{RIU}^{-1}\) , respectively. On this basis, the structure could have a great potential in optical refractive index sensing in the biological, micro and nano fields.