A hybrid dual-channel sensor based on dielectric-metal enhanced TMOKE effect

The Transverse Magneto-optic Kerr Effect (TMOKE) is a magneto-optical phenomenon under the action of an external magnetic field and has important application value in the fields of magnetism and nanoscience. However, due to the limitation of high loss of traditional ferromagnetic materials, the sensor structure is mostly single channel, which restricts its wide application. In this paper, a novel dual-channel sensing structure consisting of a one-dimensional array of bismuth iron garnet: yttrium iron garnet (BIG: YIG) nanowires, gold film and silica stack is designed by finite element method. The influence of nanowire length, BIG: YIG thickness, and SiO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> thickness on TMOKE response was studied. The results show that both the magnetic dipole resonance mode in the nanowires and the plasmon polarization-mode at the interface of the dielectric gold film show good refractive index sensing ability. The sensitivity of mode 1 is 559 nm RIU<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup>, and the sensitivity of mode 2 is 279 nm RIU<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup>. The high resolution dual-channel feature of the structure provides a theoretical basis for the application of multi-channel sensing based on TMOKE and grating mode.