High Resolution and Stability Self-Reference Plasmonic Sensor With Metallic Grating on Multilayered Dielectric Cavity Substrate

In order to improve the sensing performance of surface plasmon resonance (SPR) refractive index (RI) sensor and avoid the negative effect of various environmental factors, a self-reference plasmonic sensor with high resolution and stability based on the combination of metallic grating and multilayered dielectric cavity is proposed in this article. The sensing mode, based on SPR in the metallic grating, is sensitive to the RI variations of the analyte. The guided mode resonances (GMRs), excited by the multilayered dielectric cavity, can be served as self-references due to the insensitivity to the analyte’s RI variations. It is verified that the sensitivity of 500 nm/RIU is achieved, and the smallest sensitivity of self-reference resonance is 0.83 nm/RIU; thus, the sensitivity ratio (stability) is up to 602. Also, a large figure of merit (FOM) of 238 RIU−1 in the sensor is realized and a high-quality factor of 4668 of self-reference mode with high resolution is achieved, which is much better than that of the previous works. The results provide a theoretical basis to design a highly sensitive self-reference plasmonic sensor and have a potential application in the industrial measuring instruments such as the sensor to measure water content in heavy oil.