Highly sensitive dual eccentric-core D-type PQF-SPR methane sensor

A novel, to our knowledge, photonic quasi-crystal fiber surface plasmon resonance methane sensor with high sensitivity is designed and analyzed. The dual eccentric-core D-shaped structure enhances the surface plasmon resonance effect. The groove is fabricated on the D-shaped surface, and then zinc oxide and gold films are sequentially deposited on the surface of the grooved structure. Finally, a methane-sensitive film is deposited. The effects of the structural parameters on the sensing properties are analyzed by finite element analysis. The results show that the optimal sensitivity and average wavelength sensitivity are 140 nm/% and 71.43 nm/% for methane concentrations in the range of 0%-3.5%. Owing to its small size, high sensitivity, and real-time online monitoring capabilities, the sensor has significant commercial potential in methane leakage detection.