Magneto-Optical Activity in High Index Dielectric Nanoantennas

Sousa, N. de; Froufe‐Pérez, Luis S.; Sáenz, Juan José; García‐Martín, Antonio

doi:10.1038/srep30803

Cited by 44 publications

(46 citation statements)

References 58 publications

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“…Indeed, the magneto-optical control of the resonant behavior in plasmonic systems, and the complementary enhancement of the magneto-optical response due to the same resonances, is behind the success of the field of magnetoplasmonics [13]. In the last few years, the standard magnetoplasmonic system exhibiting electric resonances has been extended to consider other situations, such us the exploitation of magnetic resonances [14][15][16], or even the control of thermal radiation and radiative heat transfer at room temperature [17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Magneto-optical Stern-Gerlach forces and nonreciprocal torques on small particles

Edelstein

Abraham-Ekeroth

Serena

et al. 2019

Phys. Rev. Research

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In this paper we calculate the optical forces and torques caused by the presence of a sizable magneto-optical effect. We find a conservative force proportional to the gradient of the spin density of the light field and an extinction force proportional to the helicity of the light field. The conservative interaction allows for a spin-selective, magnetic field based Stern-Gerlach experiment, capable of differentiating between right and left circular polarizations. We also prove that by using a spinless linearly polarized plane wave, the magneto-optical effect allows for the existence of a permanent nonreciprocal torque, proportional to the intensity of the light field.

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Section: Introductionmentioning

confidence: 99%

Magneto-optical Stern-Gerlach forces and nonreciprocal torques on small particles

Edelstein

Abraham-Ekeroth

Serena

et al. 2019

Phys. Rev. Research

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“…In order to quantify these near-field results in a more comprehensive way, and reveal the exact spectral positions of the plasmonic resonances, we calculate the induced dipole moment in the AuNP. In the small particle limit, the dipole moment induced in the AuNP, which is embedded in the dielectric Bi: YIG, is given by the following formula: 40,41…”

Section: Near-field Simulations and Analysismentioning

confidence: 99%

“…This resonance is the result of polarization coupling, and it is mediated through the magneto-optical properties of Bi:YIG, giving rise to the broadband enhancement of the polarization conversion. 40,41 Indeed, if we express the complex oscillating electric dipole in the AuNP as p = α Au E i , where E i stands for the electric field of the incident light, then it can be shown that in linear response of ϵ yz :…”

Section: Far-field Simulations and Analysismentioning

confidence: 99%

Near-field mechanism of the enhanced broadband magneto-optical activity of hybrid Au loaded Bi:YIG

et al. 2020

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“…[13] Such periodic phase gradients have been employed for the efficient coupling of light into surface modes [14] and for the development of metalenses. [17,18] Silicon-based metamaterials have been the base to create phase gradients by changing the geometry and distribution of the nanostructures on the surface. [17,18] Silicon-based metamaterials have been the base to create phase gradients by changing the geometry and distribution of the nanostructures on the surface.…”

Section: Doi: 101002/adom201600933mentioning

confidence: 99%

Metamirrors Based on Arrays of Silicon Nanowires with Height Gradients

Otte

García‐Martín

Borrisé

et al. 2017

Advanced Optical Materials

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CommuniCation(1 of 5) 1600933 bersome due to the technical complexity required to achieve high spatial resolution.Herein we show that a careful design of the nanostructure height is indeed an efficient way to spatially tune the optical properties in high-index dielectric metamaterials. We demonstrate that arrays of silicon nanowires with tailored height gradients can generate phase gradients to develop metamirrors enabling light focusing in arbitrary shapes. In addition, the combination of height gradients and nanowires with anisotropic cross-section permits simultaneous light focusing and strong polarization conversion in the focused light. Such height-induced phase gradients can complement recently developed planar phase gradient metamaterials [21,22] to achieve even stronger lensing effects.We employ a recently developed fabrication method based on mechanically controlled metal-assisted chemical etching of silicon [23] to obtain ordered arrays of Si nanowires with height gradients. This fabrication method makes use of a thin gold layer comprising an array of nanoholes as catalyst to etch the silicon substrate. During the etching process the catalytic metal mesh is plastically deformed, thereby generating the mechanical stress that spatially modulates the etching rate and gives rise to the array of nanowires with height gradients. The height gradients can be tuned by varying the stiffness of the catalytic metal mesh, i.e., by modifying the size and shape of the nanoholes array, the edge-to-edge separation distance between nanoholes, and the metal thickness. All the metamirrors shown in this work are produced using 20 nm thick gold films and the same etching conditions of ref. [23] , with an etching time of 2 min. The height gradients could be larger by increasing etching time and by designing rupture points in the catalytic metal film. [23] The Si nanowire metamirror concept is shown in Figure 1a, which displays a circular array of cylindrical nanowires with height gradients in the radial direction, i.e., the height of the nanowires increases toward the center of the array. In the fabricated example of Figure 1b, the diameter of the array is 10 µm, the pitch is 300 nm, and the nanowires height increases from zero at the border of the array, up to 500 nm at its center. In all the arrays in this work, the 20 nm Au film used for etching is kept at the bottom of the array to increase the reflectivity of the metamirror. In these arrays, the radial height variation is converted into a radial phase variation in the light reflected by the array, which strongly depends on the nanowire diameter and pitch.As Figure 1d shows, such radial phase gradient enables tight focusing the reflected light within a spot with a focal length of 12 µm. Since the nanowires have circular cross-sections, the focusing effect in Figure 1 is polarization insensitive. Similar focusing behavior can be theoretically observed in finite difference time domain (FDTD) calculations of circular arrays of cylindrical nanowires with equivalent radial hei...

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Magneto-Optical Activity in High Index Dielectric Nanoantennas

Cited by 44 publications

References 58 publications

Magneto-optical Stern-Gerlach forces and nonreciprocal torques on small particles

Magneto-optical Stern-Gerlach forces and nonreciprocal torques on small particles

Near-field mechanism of the enhanced broadband magneto-optical activity of hybrid Au loaded Bi:YIG

Metamirrors Based on Arrays of Silicon Nanowires with Height Gradients

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