MIM plasmonic sensors based on single-side ring cavity with one stub and their applications
Yiping Sun, Desheng Qu, Qiaohua Wu, Chunlei Li
Abstract
Abstract A plasmonic sensor is proposed, comprising a metal–insulator–metal (MIM) straight waveguide and a ring cavity with one stub (RCS). Using the finite element method, its transport properties are simulated and systematically analyzed. By optimizing the structure parameters, the sensor obtains the maximum sensitivity ( S ) of 2010 nm/RIU and the maximum figure of merit ( FOM ) of 49219.04 RIU −1 . It demonstrates a sensing resolution ( SR ) of 4.98 × 10 −7 RIU in the detection of refractive index variation. Based on the optimized parameters, temperature sensing is investigated utilizing Polydimethylsiloxane (PDMS) as the temperature-sensitive medium, and the temperature sensitivity is found to be −0.90 nm/°C. In addition, multiple independently tunable resonances are achieved by adding a ring cavity (RC) above the straight waveguide. This derived structure enables the simultaneous detection of electrolyte samples (Na + and K + ) in blood with bio-sensing sensitivities reaching 0.1833 nm·dL/mg and 0.2 nm·dL/mg. These results have directive significance for the development of multifunctional and ultra-compact plasmonic sensor.