A high magnetic field sensitivity PCF‐SPR sensor working in the near‐infrared wavelength band

Abstract A novel form of photonic crystal fiber (PCF) magnetic field sensor, utilizing surface plasmon resonance, has been developed and investigated. By depositing a layer of gold onto the interior surface of the left‐sided air hole and introducing magnetic fluid into the aperture to detect magnetic field changes, the plasma resonance effect was ingeniously combined with a dual‐core PCF to achieve magnetic field measurement. The displacement of the loss peak in the output spectrum was observed to gain insights into the magnetic field changes. By means of modulations in the thickness of the gold film, and the spacing and size of the air holes, the optimal parameters for the sensor were obtained. The optimized sensor exhibited a maximum magnetic field sensitivity of up to 6.23 nm/Oe, and the magnetic field detection resolution was approximately 10 μT, enabling precise detection of weak magnetic fields. This fiber sensor boasts a simple structure, ease of production, high sensitivity, and robust environmental adaptability, making it an attractive option for implementation.