Magneto-optical response enhanced by Mie resonances in nanoantennas

Control of light by an external magnetic field is one of the important methods for modulation of its intensity and polarisation. Magneto-optical effects at the nanoscale are usually observed in magnetophotonic crystals, nanostructured hybrid materials or magnetoplasmonic crystals. An indirect action of an external magnetic field (e.g. through the Faraday effect) is explained by the fact that natural materials exhibit negligible magnetism at optical frequencies. However, the concept of metamaterials overcome this limitation imposed by nature by designing artificial subwavelength meta-atoms that support a strong magnetic response, usually termed as optical magnetism, even when they are made of nonmagnetic materials. The fundamental question is what would be the effect of the interaction between an external magnetic field and an optically-induced magnetic response of metamaterial structures. Here we make the first step toward answering this fundamental question and demonstrate the multifold enhancement of the magneto-optical response of nanoantenna lattices due to the optical magnetism.Comment: 7 pages, 5 figure

The correlation between magneto-optical response and magnetic dipole resonance excitation in subwavelength silicon-nickel nanogratings

The advantages of gyrotopic materials are combined with the field of high-index metamaterials. The enhancement of the magneto-optical response in the spectral vicinity of the magnetic dipole resonance of a dielectric silicon nanodisks is numerically shown.This work was performed in Lomonosov Moscow State University and was supported by Russian Ministry of Education and Science (grant № 14. W03.31.0008

Light-stimulated adaptive artificial synapse based on nanocrystalline metal-oxide film

Artificial synapses utilizing spike signals are essential elements of new generation brain-inspired computers. In this paper, we realize light-stimulated adaptive artificial synapse based on nanocrystalline zinc oxide film. The artificial synapse photoconductivity shows spike-type signal response, long and short-term memory (LTM and STM), STM-to-LTM transition and paired-pulse facilitation. It is also retaining the memory of previous exposures and demonstrates spike-frequency adaptation properties. A way to implement neurons with synaptic depression, tonic excitation, and delayed accelerating types of response under the influence of repetitive light signals is discussed. The developed artificial synapse is able to become a key element of neuromorphic chips and neuromorphic sensorics systems

Intensity-dependent reflectance modulation of femtosecond laser pulses in GaAs nanocylinders with magnetic resonances

Abstract We experimentally demonstrate modulation of reflectance in periodic arrays of subwavelength gallium arsenide nanocylinders with Mie-type resonances due to absorption saturation and changes in the refractive index of the semiconductor material of metasurface. The intensity-dependent reflectance modulation of up to 30% in the vicinity of the magnetic dipole resonance at a low laser fluence below 200 μ J/cm 2 is shown by I-scan measurements

Efficient Light Coupling and Purcell Effect Enhancement for Interlayer Exciton Emitters in 2D Heterostructures Combined with SiN Nanoparticles

Optimal design of a silicon nitride waveguide structure composed of resonant nanoantennas for efficient light coupling with interlayer exciton emitters in a MoSe2–WSe2 heterostructure is proposed. Numerical simulations demonstrate up to eight times coupling efficiency improvement and twelve times Purcell effect enhancement in comparison with a conventional strip waveguide. Achieved results can be beneficial for development of on-chip non-classical light sources

Manipulating the light intensity by magnetophotonic metasurfaces

We study numerically the possibility of controlling light properties by means of an external magnetic field. Considerable changes in the shape, value, and spectral position of the magneto-optical response are demonstrated in Voigt geometry for the transmitted light depending on the parameters of the magnetophotonic metasurface made up of nickel/silicon nanoparticles. The spectral overlapping of the fundamental magnetic and electric dipole Mie resonances leads to interference with a strong modification of phase relations, which manifests itself through an enhanced magneto-optical signal

Magneto-Optical Response Enhanced by Mie Resonances in Nanoantennas

We demonstrate both experimentally and numerically multifold enhancement of magneto-optical effects in subwavelength dielectric nanostructures with a magnetic surrounding exhibiting localized magnetic Mie resonances. We employ amorphous silicon nanodisks covered with a thin nickel film and achieve the 5-fold enhancement of the magneto-optical response of the hybrid magnetophotonic array of nanodisks in comparison with a thin nickel film deposited on a flat silica substrate. Our findings allow for a new basis for active and nonreciprocal photonic nanostructures and metadevices, which could be tuned by an external magnetic field

Magneto-optical effects from nanoparticles enhanced by mie resonances

Control of light by an external magnetic field is one of the important methods for modulation of its intensity and polarization. Magneto-optical effects at the nanoscale are usually observed in nanostructured hybrid materials or magnetoplasmonic crystals. In this work, we combine the advantages of all-dielectric resonant nanostructures and magnetic materials for creating compact active magneto-optical metadevices. High-index nanostructures offer novel opportunities for controlling light at the nanoscale based on a strong localization of both electric and magnetic fields in such structures near the corresponding Mie resonance [1]. This fact makes them similar to plasmonic nanostructures with clear advantage that all-dielectric meta-optics structures composed of nanoparticles with high refractive index can overcome this limit and initiate a new platform for nanophotonic metadevices [2]. As the important next step in this field, we consider a control of optical properties by an applied magnetic field, known to be an effective tool for many plasmonic structures [3,4]

Nonlinear Light Generation Driven by Collective Magnetic Modes in Oligomers of Silicon Nanoparticles Excited by Vector Beams

We demonstrated two orders of magnitude enhancement of the third-harmonic intensity for isolated nanoclusters of silicon nanoparticles illuminated by normally incident azimuthally polarized cylindrical vector beams at the wavelength of oligomer's out-of-plane magnetic mode

Third-harmonic generation from Mie-type resonances of isolated all-dielectric nanoparticles

Subwavelength silicon nanoparticles are known to support strongly localized Mie-type modes, including those with resonant electric and magnetic dipolar polarizabilities. Here we compare experimentally the efficiency of the third-harmonic generation from isolated silicon nanodiscs for resonant excitation at the two types of dipolar resonances. Using nonlinear spectroscopy, we observe that the magnetic dipolar mode yields more efficient third-harmonic radiation in contrast to the electric dipolar (ED) mode. This is further supported by full-wave numerical simulations, where the volume-integrated local fields and the directly simulated nonlinear response are shown to be negligible at the ED resonance compared with the magnetic one.The authors acknowledge financial support from Russian Foundation for Basic Research (grant nos. 16-29-11811 and 16-02-01092) and the Australian Research Council