NiFe₂O₄ Ferrofluid to Detect Magnetic Field Using Microfiber Interferometry

Vector Magnetic Field Sensing at Tiny Angles Through a Nanofluid Functionalized Ultrathin Taper Interferometer

“…Due to the disparity in propagation constants between core and cladding modes, an interference pattern is recorded at the output port of this sensing arm. This pattern is quick reactive for the changes happen in the surrounding environment of the taper section of the sensor due to modification in the anisotropy of MNPs' clusters available in MF [4,5,14]. The angle that exists between the easy axis of the particle and the direction that the externally applied field plays a role in determining the magnetization of an MNP [15].…”

“…A pictorial representation of the fabricated optical sensing device with changes in the behaviour of the available nanoparticles in the environment around the slender fiber located inside the silica glass capillary in the presence/absence of an applied external magnetic field is shown in Fig 1(a). When an SMF-28e fiber core is tapered, its core mode modulates with thinning of its core diameter, which results in higherorder modes (LP0m) being transmitted [4,5,14]. The evanescent field of the exciting cladding modes is strongly influenced by the surrounding medium in the tapered portion of the fiber optic scheme [14].…”

“…When an SMF-28e fiber core is tapered, its core mode modulates with thinning of its core diameter, which results in higherorder modes (LP0m) being transmitted [4,5,14]. The evanescent field of the exciting cladding modes is strongly influenced by the surrounding medium in the tapered portion of the fiber optic scheme [14]. After the up-taper region of the sensing arm is completed, these modes (LP01 and LP0m) gradually couple back to LP01 [14].…”

“…The evanescent field of the exciting cladding modes is strongly influenced by the surrounding medium in the tapered portion of the fiber optic scheme [14]. After the up-taper region of the sensing arm is completed, these modes (LP01 and LP0m) gradually couple back to LP01 [14]. Due to the disparity in propagation constants between core and cladding modes, an interference pattern is recorded at the output port of this sensing arm.…”

“…As illustrated from Fig. 1 (b), without an outer magnetic field (i.e., H = 0), the dielectric isotropic MF maintains the MNPs' random distribution in an isotropic state [9,14]. But when the magnetic field is not zero (H # 0), ferromagnetic NPs that are distributed in the MF become angled along H [see Fig.…”