Enhancement of magneto-optical effects by a single 1D all dielectric resonant grating

Abstract

We demonstrate theoretically the enhancement of the four first-order magneto-optical effects using an all-dielectric 1D resonant grating. The modeled structure was designed for the Faraday effect at normal incidence at a wavelength of 1.55 µm for which the calculated improvement is shown to be one hundred times the off-resonance values. At 1° incidence, polar and longitudinal Kerr effects were also improved, showing polarization rotations up to 14°. For the same incidence conditions, transverse magneto optical Kerr effect was also improved, leading to a reflectance difference of 12% for a reflectance intensity of 40%. These results are interesting for the development of magnetic-field sensors capable of detecting of several components of the field.

Deep‐UV Lithography of Nanocomposite Thin Films into Magnetooptical Gratings with Submicron Periodicity

“…A possibility of the enhancement of the MO effects by one free-space dielectric grating has been theoretically demonstrated. [33,34]. The first experimental results were obtained for a highdielectric-index impregnated grating template, [33] with an MNP-doped mineral sol-gel.…”

“…The corresponding simulated structure took into account the dispersion of the refractive index of the photostructurable nanocomposite. MO modelling was performed using a custom RCWA code, [33] taking into account the entire permittivity tensor. [35] The Fourier modal method (FMM) or RCWA is the most suitable numerical method for analyzing the interactions of electromagnetic waves with periodic diffractive structures.…”

“…A possibility of the enhancement of the MO effects by one free‐space dielectric grating has been theoretically demonstrated [33,34] . The first experimental results were obtained for a high‐dielectric‐index impregnated grating template, [33] with an MNP‐doped mineral sol‐gel. The possibility of photopatterning a composite material, demonstrated above, suggests the possibility to fabricate MO gratings without high‐index templates, which would reduce the number of fabrication steps as well as the process cost.…”

All-dielectric magnetic metasurface for advanced light control in dual polarizations combined with high-Q resonances

“…At the same time, all-dielectric nanostructures 39 are promising in the sense that resonance high quality factors and transparency might be combined with high magnetooptical modulation efficiencies. The 1D 40 , 41 and 2D 42 all-dielectric magnetic gratings and nanoparticles 43 were numerically predicted to increase some magneto-optical effects. However, fabrication of such complex shapes is challenging, and, on the other hand, the resulting optical response would be significantly affected not only by the material losses, but also by the surface roughness and fabrication inaccuracies that are neglected in these theoretical studies 40 – 43 .…”

“…The 1D 40 , 41 and 2D 42 all-dielectric magnetic gratings and nanoparticles 43 were numerically predicted to increase some magneto-optical effects. However, fabrication of such complex shapes is challenging, and, on the other hand, the resulting optical response would be significantly affected not only by the material losses, but also by the surface roughness and fabrication inaccuracies that are neglected in these theoretical studies 40 – 43 . Although recent experimental studies 44 reveal the enhancement of TMOKE in 1D all-dielectric gratings, it is still observed only for p-polarized illumination and completely vanishes for s-polarized light.…”