High sensitivity plasmonic refractive index sensing and its application for human blood group identification

- High sensitivity plasmonic sensor with silver nanorods in square resonator is proposed.
- The resonance wavelengths having a linear relationship with the refractive index of the materials under detecting.
- The refractive index sensitivity values can be obtained as high as 2320 nm/RIU..
- Its applicability is show for the detection of different human blood groups (A, B, and O).

An enhanced structure for compact and high sensitivity plasmonic refractive index sensor by using the coupling of two metal-insulator-metal (MIM) waveguides with a silver nanorods array embedded into a square resonator is proposed and analyzed in this paper. We placed silver nanorods inside the resonator due to their unique optical properties in nanoscale confinement and low propagation losses. Based on obtained results, the resonance wavelengths of the sensor having an approximate linear relationship with the refractive index of the materials under detecting that are placed into the square resonator. With an optimum design and considering a tradeoff among detected power, structure size and sensitivity, the finite difference time domain simulations show that the refractive index and temperature sensitivity values can be obtained as high as 2320 nm per refractive index unit (RIU) and 0.84 nm/°C. The achieved sensor can be used in nanophotonic and plasmonic integrated circuits and in this research; we show its applicability for the detection of different human blood groups as well.