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A Magnetic Field Fiber Optic Sensor with Magneto-optic Polymers and Nanoparticle Core-Shell Polymers
N. Peyghambarian, B. Amirsolaimani, P. Gangopadhyay, S. Showghi, L. Lacomb, J. Pyun, A. Persoons and R. A. Norwood

Miniaturized magnetic field sensors have become increasingly important in various applications, such as geophysical exploration for minerals and oil, volcanology, earthquake studies, and bio-medical imaging. Existing magnetometers lack either the required spatial or the temporal resolution or are restricted to costly shielded labs and cannot operate in an unshielded environment. Increasing the spatio-temporal resolution would allow for real-time measurements of magnetic fluctuations with high resolution. Here we report on a new nanocomposite-based system for miniaturized magnetic field sensing. The sensor is based on Dy3+ -doped magnetite and cobalt ferrite nano-particles dispersed in a polymer matrix. Operation has been demonstrated at room temperature and in an unshielded environment. A compact fiber-optic interferometer is used as the detection mechanism with 20 fT/√Hz sensitivity. We investigated the magnetic field response of the sensor and demonstrated the measurement of the human heartbeat as a potential application.

Keywords: Magnetic field sensor, magneto-optic polymer, nanocore shell polymer, polarization rotation, fiber optic interferometer

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