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- 2019
- polycrystalline ferrite-garnet
- magnetoplasmonic crystals
- magnetooptical effects
- deposition
- ion-beam methods
- sputtering
- plasmon resonance
- Physics
- Moscow Technological University
- Moscow State University
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Magnetic field sensor based on magnetoplasmonic crystal
摘要： Here we report on designing a magnetic field sensor based on magnetoplasmonic crystal made of noble and ferromagnetic metals deposited on one-dimensional subwavelength grating. The experimental data demonstrate resonant transverse magneto-optical Kerr effect (TMOKE) at a narrow spectral region of 50 nm corresponding to the surface plasmon-polaritons excitation and maximum modulation of the reflected light intensity of 4.5% in a modulating magnetic field with the magnitude of 16 Oe. Dependences of TMOKE on external alternating current (AC) and direct current (DC) magnetic field demonstrate that it is a possibility to use the magnetoplasmonic crystal as a high-sensitive sensing probe. The achieved sensitivity to DC magnetic field is up to 10?6 Oe at local area of 1 mm2.
关键词： sensitivity,surface plasmon-polaritons,transverse magneto-optical Kerr effect,magnetic field sensor,magnetoplasmonic crystal
更新于2025-09-23 15:21:01
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Enhanced magnetic modulation of light polarization exploiting hybridization with multipolar dark plasmons in magnetoplasmonic nanocavities
摘要： Enhancing magneto-optical effects is crucial for reducing the size of key photonic devices based on the non-reciprocal propagation of light and to enable active nanophotonics. Here, we disclose a currently unexplored approach that exploits hybridization with multipolar dark modes in specially designed magnetoplasmonic nanocavities to achieve a large enhancement of the magneto-optically induced modulation of light polarization. The broken geometrical symmetry of the design enables coupling with free-space light and hybridization of the multipolar dark modes of a plasmonic ring nanoresonator with the dipolar localized plasmon resonance of the ferromagnetic disk placed inside the ring. This hybridization results in a low-radiant multipolar Fano resonance that drives a strongly enhanced magneto-optically induced localized plasmon. The large amplification of the magneto-optical response of the nanocavity is the result of the large magneto-optically induced change in light polarization produced by the strongly enhanced radiant magneto-optical dipole, which is achieved by avoiding the simultaneous enhancement of re-emitted light with incident polarization by the multipolar Fano resonance. The partial compensation of the magneto-optically induced polarization change caused by the large re-emission of light with the original polarization is a critical limitation of the magnetoplasmonic designs explored thus far and that is overcome by the approach proposed here.
关键词： nanophotonics,magnetoplasmonic nanocavities,magneto-optical effects,light polarization modulation,multipolar dark modes
更新于2025-09-23 15:21:01
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Porosity-Controllable Magnetoplasmonic Nanoparticles and Their Assembled Arrays
摘要： Control of the chemical and physical properties of nanoscale colloids and their nanoassemblies remains a challenging issue for enhancing the performance and functionalities of nanodevices. In this study, we report a post-synthesis etching method to tailor the porosity of the Fe3O4 shells coating on Ag NPs, establishing a facile but effective approach to regulate the chemical and optical properties of the colloids and their assembled structures. As the shell porosity increases, the NPs are transformed, producing enhanced catalytic activity and the surface-enhanced Raman spectroscopy (SERS) effect, which results from enhanced chemical diffusion into the Ag core. Magnetoplasmonic (MagPlas) one- (1D) and two- (2D) dimensional arrays fabricated using these porosity-controllable NPs exhibit intriguing plasmon properties that are strongly affected by the porosity of the particle shell. Furthermore, the bright coloration of the 2D arrays is tuned by changing the shell porosity or introducing an additional metallic layer. Such 1D and 2D porous MagPlas metastructures possessing Fe3O4 shells with tunable porosities are a fulcrum for developing recyclable catalysts and tunable optical filters with optimized activity, selectivity, and sensitivity, as well as color displays and sensing platforms.
关键词： coloration,porosity,metamaterial,plasmon interaction,magnetoplasmonic
更新于2025-09-23 15:21:01
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Helical Magnetic Field-Induced Real-Time Plasmonic Chirality Modulation
摘要： Astrophysical phenomenon mimetic helical magnetic field (hB)-assisted self-assembly is herein introduced to build helical superstructures that display chiroptical properties. As a building block, magnetoplasmonic (MagPlas) Ag@Fe3O4 core-shell nanoparticles are used to guide plasmonic Ag nanoparticles onto a helical magnetic flux. The chirality of the assembled helical structures and tailored circular dichroism are successfully tuned in real-time, and the handedness of the assembled structures is dynamically switched by the hB at the millisecond level, which is at least 6,000-fold faster than other template-assisted methods. The peak position of circular dichroism can be reconfigured by altering the plasmonic resonance or coupling by controlling the size of the Ag core and magnetic flux density. The hB-induced chirality modulation represents a method to control the polarization state of light at the nexus of plasmonics, magnetic self-assembly, colloidal science, liquid crystals, and chirality. It presents active and dynamic chiral assemblies of magnetoplasmonic nanomaterials, enabling further practical applications in optical devices.
关键词： magnetoplasmonic nanoparticles,helical magnetic field (hB),self-assembly,dynamic chirality,real-time modulation
更新于2025-09-23 15:19:57
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Switching the Optical Chirality in Magnetoplasmonic Metasurfaces Using Applied Magnetic Fields
摘要： Chiral nanophotonic devices are promising candidates for chiral molecule sensing, polarization of diverse nanophotonics, and display technologies. Active chiral nanophotonic devices, where the optical chirality can be controlled by an external stimulus has triggered great research interest. However, efficient modulation of the optical chirality has been challenging. Here, we demonstrate switching of the extrinsic chirality by applied magnetic fields in a magnetoplasmonic metasurface device based on a magneto-optical oxide material, Ce1Y2Fe5O12 (Ce:YIG). Due to the low optical loss and strong magneto-optical effect of Ce:YIG, we experimentally demonstrated giant and continuous far-field circular dichroism (CD) modulation by applied magnetic fields from ?0.6 ± 0.2° to +1.9 ± 0.1° at 950 nm wavelength under glancing incident conditions. The far-field CD modulation is due to both magneto-optical circular dichroism and near-field modulation of the superchiral fields by applied magnetic fields. Finally, we demonstrate magnetic-field-tunable chiral imaging in millimeter-scale magnetoplasmonic metasurfaces fabricated using self-assembly.
关键词： optical chirality,magneto-optical effect,magnetoplasmonic,metasurface,circular dichroism,magnetic oxides
更新于2025-09-23 15:19:57
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[IEEE 2019 Thirteenth International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials) - Rome, Italy (2019.9.16-2019.9.21)] 2019 Thirteenth International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials) - Highly sensitive magnetometry method based on the magnetoplasmonic crystal
摘要： A novel concept of the room-temperature magnetoplasmonic magnetic field sensor with high sensitivity and spatial resolution is presented. The advanced flux-gate technique is used. Magnetization of the fully saturated magnetic film is rotated in the film plane and the monitored magnetic field is measured by detecting variation of optical transmittance through the sensing element. The sensing element is a magnetoplasmonic crystal consisting of a gold grating with subwavelength period deposited on a thin transparent dielectric film of bismuth substituted iron-garnet. Geometrical parameters of the magnetoplasmonic crystals are adjusted to have pronounced resonances of the longitudinal magneto-photonic intensity effect (LMPIE). The experimental study revealed that such approach allows one to reach the 2nT sensitivity level which was limited by the noise of the laser. The demonstrated magnetoplasmonic magnetometry method is promising for mapping and visualization of ultra-small magnetic fields.
关键词： magnetic field sensor,magnetometry,LMPIE,magnetoplasmonic crystal
更新于2025-09-16 10:30:52
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Tunable multimodal magnetoplasmonic metasurfaces
摘要： The spectrally controllable enhancement of the transverse magneto-optical Kerr effect is realized in 2D hybrid metal-dielectric magnetoplasmonic metasurfaces. The light diffracted at different interfaces allows one to manipulate light phase in the condition of plasmonic and waveguiding resonance excitation controllable via the azimuthal angle. The multimodal nature of the system provides the flexible tunability of its magneto-optical response.
关键词： azimuthal angle,magneto-optical Kerr effect,magnetoplasmonic metasurfaces,plasmonic resonance,waveguiding resonance
更新于2025-09-16 10:30:52
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Efficiency evaluation of the transverse magneto-optical Kerr effect in magnetoplasmonic structures
摘要： In this study the new approach to the efficiency evaluation of the transverse magneto-optical Kerr effect is considered. To assess the prospects for the practical use of structures based on TMOKE, the Figure of Merit (FOM) parameter is introduced, which is the product of the reflected/transmitted light intensity and the Kerr signal of the structure. Kerr signal defined as absolute value of the difference of light intensities at opposite magnetizations. It is shown that parameter Figure of Merit (FOM) in proposed form can give more information than the most commonly used relative value of TMOKE. The advantages of the introduced parameter are demonstrated on the example of a magnetoplasmonic structure with thin magnetite films.
关键词： transverse magneto-optical Kerr effect,magnetoplasmonic structures,Figure of Merit,TMOKE
更新于2025-09-12 10:27:22
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Wide-band enhancement of the transverse magneto-optical Kerr effect in magnetite-based plasmonic crystals
摘要： The transverse magneto-optical Kerr effect (TMOKE) in magnetite-based magnetoplasmonic crystals is studied experimentally and theoretically. We analyze angle-resolved TMOKE spectra from two types of structures where noble metallic stripes are incorporated inside a thin magnetite film or located on top of a homogeneous film. A multiple-wide-band enhancement of the TMOKE signal in transmission is demonstrated. The complex dielectric permittivity and gyration are experimentally determined using the ellipsometry technique as well as Faraday rotation and ellipticity measurements. The obtained parameters are used in rigorous coupled-wave analysis (RCWA) calculations for studying the optical resonances. Our RCWA calculations of transmittance and TMOKE are in good agreement with the experimental data. The role of guiding and plasmonic modes in the TMOKE enhancement is revealed. We demonstrate that the TMOKE provides rich information about the studied optical resonances.
关键词： transverse magneto-optical Kerr effect,ellipticity measurements,gyration,magnetoplasmonic crystals,Faraday rotation,dielectric permittivity,optical resonances,RCWA,magnetite,TMOKE
更新于2025-09-12 10:27:22
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Double-Lattice Magnetoplasmonic Structures Based on BIG and Perforated Gold Films
摘要： A method of manufacturing double-lattice magnetoplasmonic crystals with the structure (Au/BIG)2, in which the plasmon gold lattices are displaced relative to each other by half a period, has been presented. Gold films with thicknesses of about 40 nm have been formed by the ion-beam sputtering–deposition method, while the adhesive properties of the films allow the dimensional etching by a sharp-focused ion beam. It has been shown that the formation of the second plasmon lattice located on top of the 100 nm thick garnet layer allows the preserving of the periodicity of the first Au lattice. However, there is a significant influence of diffusion spreading on the lower lattice material, which leads to a decrease in its density. The dependence of the intensity magnetooptical effect in the geometry on the transmission as a function of the thickness of the upper lattice and presence of an additional layer of Ta2O5 has been studied.
关键词： polycrystalline ferrite-garnet,magnetoplasmonic crystals,magnetooptical effects,deposition,ion-beam methods,sputtering,plasmon resonance
更新于2025-09-11 14:15:04