Magnetic Nanoparticles Functionalized Few-Mode-Fiber-Based Plasmonic Vector Magnetometer

Abstract

In this work, we demonstrate a highly-sensitive vector magnetometer based on a few-mode-fiber-based surface plasmon resonance (SPR) sensor functionalized by magnetic nanoparticles (MNPs) in liquid. To fabricate the sensor, a few-mode fiber is side-polished and coated with a gold film, forming an SPR sensor that is highly sensitive to the surrounding refractive index. The vector magnetometer operates based on the mechanism whereby the intensity and orientation of an external magnetic field alters the anisotropic aggregation of the MNPs and thus the refractive index around the fiber SPR device. This, in turn, shifts the resonance wavelength of the surface plasmon. Experimental results show the proposed sensor is very sensitive to magnetic-field intensity and orientation (0.692 nm/Oe and −11.917 nm/°, respectively). These remarkable sensitivities to both magnetic-field intensity and orientation mean that the proposed sensor can be used in applications to detect weak magnetic-field vectors.

Magnetic Field Sensor Based on a Tri-Microfiber Coupler Ring in Magnetic Fluid and a Fiber Bragg Grating

“…Magnetic sensors based on optical fiber interferometers are an excellent alternative to traditional electronic sensors due to their outstanding advantages of immunity to electromagnetic interference, compact size, and ability to operate in hazardous environments. A number of optical fiber interferometric structures have been proposed for magnetic field sensing, such as fiber gratings [4], microfiber couplers [5,6], surface plasmonic structures [7,8,9], cascaded fiber hetero-structures [10], tapered photonic crystal fibers [11], various fiber structures incorporating magnetic fluids [12], and so on. It should be noted however, that since the main research focus currently is on sensing of the magnetic field strength, most of the existing sensors cannot be used for determining the magnetic field direction.…”

“…Typically, existing fiber-optic sensors suffer from temperature-induced drift and often require additional means for temperature compensation [1,5,7,8,9], and fiber Bragg grating (FBGs) prove to be an effective tool for temperature referencing [4,6]. Finally, many of the fiber-optic sensors incorporating magnetic fluids or nanoparticles suffer from hysteresis due to their inherently slow response times [1,3].…”

Magnetite Nanoparticles: Synthesis and Applications in Optics and Nanophotonics

“…Magnetic field sensors integrated with magnetic FFs have attracted considerable attention because of their ease of fabrication, high sensitivity, and low cost [ 104 ] as well as due to their unique magneto-optical properties [ 105 ]. Cennamo et al [ 106 ] presented a novel methodology for magnetic field sensing by exploiting surface plasmon resonance (SPR) sensors based on D-shaped plastic optical fiber (POF) and magnetic fluids.…”

Research Advances on Fiber-Optic SPR Sensors with Temperature Self-Compensation

“…In addition to the inherent advantages of fiber optic sensor, the SPR sensor has the additional advantages of high detection sensitivity and label-free detection. This technology has been widely used in physical quantity measurement [ 3 , 4 , 5 , 6 , 7 ], biological quantity sensing [ 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ], and environmental monitoring [ 17 , 18 , 19 ]. However, temperature variation affects the refractive index of metals and dielectric materials, and according to the SPR resonance wavelength calculation equation [ 20 ], ( is the incident wavelength, and and are dielectric constants of the metal film and ambient medium, respectively), the resonance peak wavelength shift of the SPR due to temperature change is unavoidable.…”