Highly Sensitive Two-Parameter Anti-resonant Fiber (ARF) Sensor Based on Surface Plasmon Resonance in the Terahertz Band
摘要
A two-parameter anti-resonant fiber (ARF) sensor based on the principle of surface plasmon resonance (SPR) is designed to detect refractive index (RI) and temperature simultaneously. Graphene is coated on the externally cut negative curvature tube as the plasmonic medium to excite terahertz SPR for detecting the RI of the external liquid. In addition, polydimethylsiloxane (PDMS) is filled in the graphene-coated tube to sense the temperature of the liquid. The properties of the ARF-SPR sensor are analyzed by the finite element method. The maximum wavelength sensitivity and amplitude sensitivity of 13,888.9 µm/RIU and 87.40 RIU−1 respectively are observed at the second resonance peak for RIs between 1.3 and 1.36, and the minimum resolution is 7.2 × 10−9 RIU−1. In the temperature range of 26.85 to 76.85 °C, the first resonance peak is insensitive to the temperature, and the maximum temperature sensitivity and amplitude sensitivity of the second resonance peak are 8.4 µm/°C and 0.058 °C−1, respectively, with a resolution on the order of 10−5. This special design, boasting a simple structure, overcomes the limitations of single-parameter measurements and solves the problems of two-parameter cross-sensitivity while offering excellent sensing performance.