Nanostructured magnetic materials provide an efficient tool for light manipulation on sub-nanosecond and sub-micron scales, and allow for the observation of the novel effects which are fundamentally impossible in smooth films. For many cases of practical importance, it is vital to observe the magneto-optical intensity modulation in a dual-polarization regime. However, the nanostructures reported on up to date usually utilize a transverse Kerr effect and thus provide light modulation only for p-polarized light. We present a concept of a transparent magnetic metasurface to solve this problem, and demonstrate a novel mechanism for magneto-optical modulation. A 2D array of bismuth-substituted iron-garnet nanopillars on an ultrathin iron-garnet slab forms a metasurface supporting quasi-waveguide mode excitation. In contrast to plasmonic structures, the all-dielectric magnetic metasurface is shown to exhibit much higher transparency and superior quality-factor resonances, followed by a multifold increase in light intensity modulation. The existence of a wide variety of excited mode types allows for advanced light control: transmittance of both p- and s-polarized illumination becomes sensitive to the medium magnetization, something that is fundamentally impossible in smooth magnetic films. The proposed metasurface is very promising for sensing, magnetometry and light modulation applications.

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Plasmon enhancement of optical absorption in phthalocyanines and related compounds is a highly effective route for substantial improvement of their photophysical properties. Herein, we report the results on the comprehensive study of optical absorption in aluminum phthalocyanine complex in spherical exciton−plasmon nanostructures based on gold nanoparticles. We synthesized hybrid nanoparticles (HNPs) composed of gold cores with an average size of 19 nm coated by phthalocyanines which formed a close-packed molecular shell having a thickness of 2−4 nm. Owing to H-type aggregation of phthalocyanines at the particle surface, the self-assembled molecular shell demonstrates optical properties typical for most of the metal-phthalocyanine thin films. On the basis of the generalized Mie theory and experimental results, we simulated effective absorption spectra of phthalocyanines in HNPs and established a great enhancement of molar absorption coefficient caused by intense plasmonic near field acting on the shell (up to 8 times at λ = 535−550 nm). The enhancement factor of molar absorption coefficient is primarily governed by a degree of spectral overlap between the plasmonic and excitonic bands that can also dramatically change the absorption line shape of the phthalocyanine. In order to overcome the limitation, we have made a theoretical assessment, which demonstrates a prospect of gold nanoshells to form a plasmonic core of HNPs.

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All-dielectric metasurfaces have been attracting much attention. Low optical losses and a huge variety of optical modes provide unique possibilities for light manipulation at the nanoscale. Recent studies showed that the magneto-optical effects in such metasurfaces are enormously enhanced. Moreover, it is possible to observe novel magneto-optical effects that are absent in smooth films. Excitation of particular photonic resonances makes it possible to design the magneto-optical interaction by the metasurface design. This opens up broad opportunities for magneto-photonic metasurface applications, including optomagnetism, light modulation, sensing, magnetometry, etc.

Molecular magnetism and specifically magnetic molecules are recently gaining plenty of attention as key elements for quantum technologies, information processing, and spintronics. Transition to the nanoscale and implementation of ordered...

Light localization by metal particles of nanometer size allows to not only control the propagation of light, but also enhance magneto‐optical effects. The influence of the immersion of gold nanodisks inside a transparent magnetic medium, namely, Bi‐substituted iron garnet, is investigated, and the optimal position of the nanoparticles within the magnetic material for a strong enhancement of the effect is unraveled. Three samples with periodic arrays of Au cylinders are studied: disks on the surface of the magnetic dielectric film, inside the magnetic film, and directly under the magnetic film. The largest enhancement of the Faraday effect mediated by a localized surface plasmon resonance takes place when nanodisks are submerged inside the magnetic film at a few nanometers below its upper surface. It is shown that the most prominent influence on the Faraday effect enhancement is provided by the magnetic medium between the nanodisks. The experimental results are in good agreement with the numerical analysis.

We report the enhancement of the magneto-optical Faraday effect in a two-dimensional magnetoplasmonic grating with a square lattice. The structure consists of dielectric magnetic Bi-substituted iron garnet film with low thickness (100 nm) coated by a perforated gold layer. Enhancement of the Faraday rotation by about 2 times is shown experimentally and theoretically despite the suppression of the waveguiding modes. This happens primarily through excitation of surface plasmon polaritons propagating at the Au-garnet interface in two orthogonal directions along lattice vectors of the plasmonic grating.