High-sensitivity methane sensor composed of photonic quasi-crystal fiber based on surface plasmon resonance
Qiang Liu, Jin Zhao, Yudan Sun, Wei Liu, Chao Liu, Jingwei Lv, Tingting Lv, Yu Jiang, Binwen Li, Famei Wang, Tao Sun, Paul K. Chu
Abstract
A photonic quasi-crystal fiber (PQF) methane sensor based on surface plasmon resonance (SPR) is designed and described. The double-side polished six-fold photonic quasi-crystal fiber coated with a silver film produces enhanced SPR effects and sensitivity. A nanostructured thin film with cryptophane-E-doped polysiloxane is deposited on silver as the methane-sensitive surface layer and to mitigate oxidation of silver. The sensor is analyzed and optimized numerically by the full-vector finite element method. For methane concentrations in the range of 0% to 3.5%, the maximum sensitivity of the sensor is 8 nm/%, and the average sensitivity is 6.643 nm/%. Compared to traditional gas sensors, this sensor provides accurate sensing of methane besides offering advantages such as the low cost, miniaturized size, online monitoring, and immunity to electromagnetic field interference.