Characteristics of MoO2 Deposited C-Shaped Photonic Crystal Fiber Sensor with a Micro-Opening Based on Surface Plasmon Resonance

This paper combines molybdenum dioxide (MoO2) instead of the gold film with photonic crystal fiber (PCF) for the first time. A novel C-type micro-opening surface plasmon resonance (SPR) optical fiber sensor coated with MoO2 nanofilm is proposed. The polarization and sensing characteristics of the sensor coated with plasma film on the outer surface of the polished optical fiber are numerically analyzed by the finite element method (FEM). The simulation results show that when the plasma material deposited by the optical fiber micro-opening is noble metal gold, the sensor can realize the sensing detection of the refractive index of the analyte from 1.33 to 1.39, and the average wavelength sensitivity in the x-polarization direction reaches 1107 nm/RIU. It is most noteworthy that when the plasma coating material of the optical fiber is replaced by metal oxide MoO2, the sensor can realize the sensing detection of the refractive index of the analyte from 1.31 to 1.37, and the average sensitivity of the x-polarization direction can reach 4821 nm/RIU. By comparison, we can know that the sensor coated with plasma material MoO2 has excellent sensing characteristics. This research is of great scientific significance for expanding the application range of MoO2 materials and promoting the development of photonic crystal fiber sensors coated with new materials.