The magnetic field sensor based on the longitudinal magnetophotonic effect in a magnetoplasmonic crystal

Summary form only given. In the present work the LMPIE is used for design of the magnetic field sensor. The in-plane rotating magnetic field is applied as strong as to keep the sample saturated and the intensity of the transmitted light is measured. Due to the LMPIE the second harmonic in signal occurs. The presence of a small additional in-plane constant external magnetic field leads to distortion of the signal. The other harmonics appear, in particular the 1-st and the 3-rd, with their amplitudes being proportional to the constant field. Thus by observing the quantitative changing of the harmonics amplitudes and phases we determine the values of two planar components of the constant magnetic field. In order to prove this concept, we designed and fabricated the samples with rather low saturation magnetization of the dielectric. The samples had different parameters of the gold grating: the period differs from 320 nm to 340 nm and the air slit width differs from 70 nm to 140 nm. The rotating magnetic field of 10 Oe was formed by Helmholtz coils. The light was normally incident on the sample. The spectrum of the LMPIE for one of the samples. The obtained light modulation is 5%. Our next step was adding the constant in-plane magnetic field.