Highly-sensitive magneto-optical sensors based on thin transmission-type one-dimensional magnetophotonic crystals for the visualization of magnetic fields

We have performed a theoretical study on the case of thin magneto-optical (MO) sensors based on transmission-type one-dimensional magnetophotonic crystals (MPCs). We could achieve thin MPC structures having only two or three magnetic defect layers that lead to large Faraday rotations up to 30° at the wavelength 560 nm in the visible region. Since the sensitivity of a MO sensor depends on the thickness of the sensing film, these very thin MPCs can act as highly sensitive MO magnetic field sensors. We could achieve MPC-based sensors with sensitivities up to 0.057 °/G.