Detection Range Adjustable D-shaped Photonic Crystal Fiber Plasmonic Sensor: A comparative Study on Materials Effect

In this paper, a high-performance plasmonic surface plasmon resonance (SPR) sensor with adjustable detection range is proposed using Au in combination with TiO ₂ and Si ₃ N ₄ as the adhesive layer, respectively. We simulated and compared the effect of two attachment enhancement materials on the performance of the sensor. The results show that for the Au - TiO ₂ combination, the maximum wavelength sensitivity (WS) is 65,000 nm/RIU at the refractive index (RI) of 1.39–1.40, the wavelength interrogation resolution of 1.54 × 10 ^− 6 RIU, the sensor reaches the amplitude sensitivity (AS) of 2,429 RIU ^− 1 at RI = 1.34 and the resolution of 4.12 × 10 ^− 6 RIU with amplitude interrogation method, and the RI detection range is 1.34–1.40. For the Au - Si ₃ N ₄ combination, the maximum WS is 76,000 nm/RIU at RI between 1.39–1.40, the resolution of 1.32 × 10 ^− 6 RIU ^− 1 with wavelength interrogation and the AS is 3,040 RIU ^− 1 when RI = 1.34, the amplitude interrogation resolution of 3.29 × 10 ^− 6 RIU, and a RI range of 1.40–1.34. The sensor has an ultra-high WS and AS as well as the adjustable detection ranges of 1.31–1.41 and 1.33–1.43 by filling the supporting analyte with certain RI. We also present the fabrication process of the sensor, our sensors show great potential in different scenarios due to its superior performance and easiness of manufacturing.