Vector magnetic field characteristics of magneto-shape effect with high figure of merit based on fiber optic vernier effect

Abstract

The vector magnetic field structures utilizing magnetic fluid (MF) mainly rely on the magneto-refractive index effect (MRI), which has the low spatial resolution due to the long sensitive length. In this article, the vector magnetic field characteristics of the magneto-shape effect (MSE) are simulated and experimentally studied based on the fiber optic vernier effect. The high vector magnetic field sensitivity can be achieved under the condition of Φ128*73 μm in the sensitive area by combine the MSE and vernier effect. The distribution of magnetic field on the concavity of MF varies with magnetic field direction, giving rising to MF concavity different deformations. The magnetic field observation structure based on fiber optic vernier effect are fabricated to verify the vector magnetic field characteristics of MSE. The observation structure is subjected to one-dimensional and two-dimensional magnetic field. The test results demonstrate that the magnetic field sensibility can reach 2.36 nm/Gs, 3.88 nm/Gs and 4.52 nm/Gs under 0–55.0 Gs, 55.0–91.7 Gs and 91.7–119.2 Gs in Y direction field. The magnetic field sensibility is 0.91 nm/Gs in Z direction field. The magnetic field direction sensitivity can reach 1.16 nm/° in XY dimensional field. The structure of the MSE is very compact and the size is very small, which is very helpful for detecting the narrow space and gradient magnetic field.