SPR based magnetic-field sensing in microchannelled PCF: a numerical approach

Abstract

We propose a surface plasmon resonance (SPR) based magnetic field sensor using a microchannel incorporated side-polished photonic crystal fiber (PCF). A side polished PCF, when exposed to a high energy Gaussian pulse in the transverse direction, engraves a microchannel on the flat surface. The inner surface of the microchannel is assumed to be coated with indium tin oxide (ITO) and the microchannel is to be filled with magnetic fluid (MF). The refractive index (RI) of MF could be varied via application of magnetic field. The principle of the device is based on the excitation of surface plasmon wave at the ITO-MF interface and the corresponding shift in SPR peak due to the change in RI of MF. The presence of ITO helps in excitation of surface plasmon in the near infrared wavelength band. Through numerical analysis, we estimate the magnetic field sensitivity of the proposed device to be 564 pm Oe−1 (5.64 nm/mT) for weaker magnetic field with a maximum resolution of 0.177 Oe. Further, the proposed sensor can be utilized for intensity based magnetic field sensing where its sensitivity is of the order of 0.005/Oe.