Dynamic Field Magnetometry Using Tunable Cavity-Assisted PCF Modal Interferometer

Dynamic magnetic field detection is essential in various fields spanning over industrial monitoring to scientific explorations. The development of a high-resolution magnetometer that is operable over broad frequency range has remained elusive. In this work, we report an optical magnetometer that consists of a single-mode fiber (SMF)–photonic crystal fiber (PCF) fiber configuration and a flexible magnetic membrane, configured in the form a cavity interferometer, for the detection of dynamic magnetic field. The SMF–PCF configuration forms a modal interferometer, that is aligned with the reflective surface of the membrane, to generate fine fringes for high-resolution magnetometry. The proposed system enables detection of dynamic magnetic field intensity of order of microteslas with high sensitivity of 587 pm/
$10~\mu $
T. The noise-limited minimum detectable magnetic field intensity with the proposed system is
$13~\mu $
T/
$\surd $
Hz. The system detects field frequency over a range of 1–1000 Hz with significant signal-to-noise ratio (SNR). Besides, the magnetometer configuration is implemented for the detection of magnetic field at various in-plane angular orientations with respect to the sensor head. The cavity configuration is conveniently reconfigurable to tailor the sensitivity and operational range. The proposed magnetometer is single-ended and tunable that would find wide applications in manufacturing units, navigation systems, and environmental surveillance.