High sensitivity Fabry–Pérot interferometric magnetic sensor based on Fe3O4-doped PDMS composite thin film

Abstract A magnetic field sensor based on Fabry–Pérot interferometer (FPI) with soft gold magnetic composite film (GMCF) is proposed and demonstrated experimentally. GMCF is fabricated by Fe3O4-doped polydimethylsiloxane (PDMS) film and adhered thin gold membrane via van der Waals force. Applying an external magnetic field, GMCF can vibrate under magnetic forces and cause a change in the cavity length of FPI and hence modulates the interference spectra. Experimental results indicate that the sensor can achieve maximum sensitivity of 390 pm mT−1 under a linear magnetic field intensity ranging from 0 to 65 mT. The proposed sensor could help with magnetic field detection in complex environments.