The Longitudinal Magneto-Photonic Effect in Plasmonic Structures: Physics and Applications

Olga Borovkova Russian Quantum Center, Skolkovo, Moscow, Russia Andrey Kalish Russian Quantum Center, Skolkovo, Moscow, Russia Faculty of Physics, Lomonosov Moscow State University, Moscow, Russia Anatoly Zvezdin Russian Quantum Center, Skolkovo, Moscow, Russia Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow, Russia Vladimir Belotelov Russian Quantum Center, Skolkovo, Moscow, Russia Faculty of Physics, Lomonosov Moscow State University, Moscow, Russia

Magneto-optical effects have become the subject of active research due to the possibility of ultrafast and effective control of light properties such as polarization and intensity. Recently it was demonstrated that these effects can be enhanced in specially tailored nanostructures, in particular, in plasmonic structures. Moreover, it was shown that such structures exhibit some novel magneto-optical behavior, that is prohibited in smooth magnetic media. The example of such phenomena is the longitudinal magneto-optical effect (the LMPIE) [1].

The LMPIE takes place in one-dimensional plasmonic crystals consisting of a noble-metallic grating and a smooth magnetic dielectric film. Bi-substituted iron garnet can be taken as magnetic dielectric. This type of structure has the advantage of simultaneous high magneto-optical behavior and relatively low optical losses in comparison to structures containing ferromagnetic metals. The magnetization is directed in-plane perpendicular to the grating slits.

The LMPIE is the magnetization-induced change in optical transmittance and reflectance. The effect is of resonant nature because it is related to the excitation of the structure’s eigenmodes, namely, plasmonic and quasi-waveguide modes. The origin of the effect is the polarization transformation of the modes under external magnetic field. It allows excitation of modes that are dark in the demagnetized case and so additional resonances appear which leads to high intensity change.

It was found both theoretically and experimentally that this effect can be as high as several tens of percent.

In the present work we investigate the impact of material composition on the LMPIE. Namely, we investigate the dependence of the LMPIE on the concentration of Bi in iron garnet. For this we retrieve analytical dependences of garnet’s optical and magneto-optical parameters on concentration of Bi from experimental data and perform optimization of geometrical parameters to achieve the highest values of the LMPIE.

The LMPIE is of great practical interest because due to its giant values it can be applied to optical telecommunication devices. Aside from that, we propose to apply it for highly sensitive magnetic field sensors.

The work is supported by the Russian Science Foundation (project No. 14-32-00010).

[1] V.I. Belotelov, et al. PRB 89 045118 (2014).

o.borovkova@rqc.ru









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