Anisotropic Nanoantenna-Based Magnetoplasmonic Crystals for Highly Enhanced and Tunable Magneto-Optical Activity

Abstract

We present a novel concept of a magnetically tunable plasmonic crystal based on the excitation of Fano lattice surface modes in periodic arrays of magnetic and optically anisotropic nanoantennas. We show how coherent diffractive far-field coupling between elliptical nickel nanoantennas is governed by the two in-plane, orthogonal and spectrally detuned plasmonic responses of the individual building block, one directly induced by the incident radiation and the other induced by the application of an external magnetic field. The consequent excitation of magnetic field-induced Fano lattice surface modes leads to highly tunable and amplified magneto-optical effects as compared to a continuous film or metasurfaces made of disordered noninteracting magnetoplasmonic anisotropic nanoantennas. The concepts presented here can be exploited to design novel magnetoplasmonic sensors based on coupled localized plasmonic resonances, and nanoscale metamaterials for precise control and magnetically driven tunability of light polarization states.

Hybrid Ni/SiO2/Au dimer arrays for high-resolution refractive index sensing

“…In contrast, the resonance width of SLR modes in magnetoplasmonic nanoparticle arrays are not strictly limited by high ohmic losses in the ferromagnets. Here, the shape and size of the individual nanoparticles and lattice parameters can be utilized to design sharp resonances in magneto-optical spectra [22][23][24][25]. The improved sensing performance of arrays with a lattice constant of 500 nm compared to those with a = 400 nm in this study is a clear manifestation of this effect.…”

“…Recently, the excitation of SLRs in arrays of ferromagnetic nickel nanoparticles was demonstrated [22]. The magneto-optical activity of an ordered ferromagnetic array is larger than that of randomly distributed nanoparticles, and it tunes sensitively with the period and symmetry of the lattice [22][23][24] or the size or shape of the nanoparticles [25]. The ability to compensate for intrinsic damping via the excitation of SLR modes offers new perspectives for refractive index sensing based on magnetoplasmonic architectures.…”

The 2017 Magnetism Roadmap

“…The key challenge is to increase the strength of SO coupling without increasing the plasmon damping, due to dissipative losses. The main strategies currently pursued with conventional FMs, namely without increasing the intrinsic SO coupling, are illustrated in figure 15 and include the design and fabrication of: periodic arrangements of MP nanoantennas [105]; 3D pure FM and composite FM/NM and FM/D/NM nanostructures [106]; and 'meta-atoms', i.e. heterogeneous units comprising of multiple nanoantennas placed in proximity to enable their near-field interaction.…”

Plasmonic nanodevice with magnetic funcionalities: fabrication and characterization

“…Hence, it is difficult to achieve ferromagnetic and plasmonic behaviors in the same material. Only recently, nanostructures of Ni [14][15][16][17][18][19][20] Ni/Co [21] and permalloy antidots [22] have been reported to exhibit surface plasmons in combination with their well-known ferromagnetic character at room temperature. However, the intensity of the plasmonic resonance in these type of materials is fairly weaker than for noble metals as Au or Ag where the electromagnetic field can be increased locally up to 80 times upon excitation of surface plasmons [23].…”