SPPs based nano refractive index sensor for sodium and potassium ion concentration detection in human blood

Abstract In this paper, a micro-nano sensing configuration constructed from MIM waveguide and a semicircular cavity with annular cavity (SCAC) based on surface plasmon polaritons(SPPs) is submitted. And the sensing property of the waveguide coupling construction is investigated using the finite element method. The optimization emulation results show that the broadband mode generated by the two rectangular cavities on the bus waveguide interacts with the narrowband mode generated by the main construction SCAC, and the radiation spectroscopy of the system appears to be significantly sharp and asymmetric, which is the Fano resonance phenomenon. The impact of external environmental changes on the capability of the sensing structure was investigated by altering the geometric argument of the designed structure afterwards. The final system can achieve a sensitivity of 2600 nm RIU −1 and a figure of merit (FOM) of 47.27. It was then applied to biosensing and its sensitivity as a human sodium and potassium ion concentration detection sensor was investigated and the best can be achieved at 0.415 mgd l − 1 and 0.525 mgd l − 1 .