Magnetic field sensor based on magnetic fluid.

• Main Author: Chua, Eric Shan Qin.
• Other Authors: Chan Chi Chiu
• Format: Final Year Project
• Language: English
• Published: 2011
• Subjects: DRNTU::Science::Chemistry::Physical chemistry::Magnetochemistry
• Online Access: http://hdl.handle.net/10356/45483
• Institution: Nanyang Technological University

This project presents a magnetic field sensor based on magnetic fluid film. A magneto-optical material, the magnetic fluid film is employed to directly alter and interact with parameters of light. Together with the use of a polarization maintaining optical fiber and external magnetic field strength, the effects of birefringence and phase shift differences in a polarimetric optical setup is investigated. In addition, the thickness of the magnetic fluid film and its effect on the magnetic field sensor is discussed as well. Transmission wavelengths dips of visibility or extinction ratio of 40 dBm were obtained by using the optical spectrum analyzer and broadband amplified spontaneous emission light source. The transmission wavelength dips, coupled with varying external magnetic field strength of 0 Oe to 2000 Oe, shifted from 1nm to 3.3nm with increasing thickness of the magnetic fluid film from 20μm to 60μm. This project also demonstrates the validity of the proposed magnetic field sensor by changing the output spectrum of the transmission wavelength dips to an intensity sensor, verifying the dynamic range of this novel magnetic sensor based on the birefringence properties of the magnetic fluid film.