Observation of localized magnetic plasmon skyrmions

Abstract

Optical skyrmions have recently been constructed by tailoring vectorial near-field distributions through the interference of multiple surface plasmon polaritons, offering promising features for advanced information processing, transport and storage. Here, we provide experimental demonstration of electromagnetic skyrmions based on magnetic localized spoof plasmons (LSP) showing large topological robustness against continuous deformations, without stringent external interference conditions. By directly measuring the spatial profile of all three vectorial magnetic fields, we reveal multiple π-twist target skyrmion configurations mapped to multi-resonant near-equidistant LSP eigenmodes. The real-space skyrmion topology is robust against deformations of the meta-structure, demonstrating flexible skyrmionic textures for arbitrary shapes. The observed magnetic LSP skyrmions pave the way to ultra-compact and robust plasmonic devices, such as flexible sensors, wearable electronics and ultra-compact antennas.

Topological quasiparticles of light: Optical skyrmions and beyond

“…Localized spoof-plasmon devices were designed to generate such optical target skyrmions in the magnetic field with controllable radial kπ twist degree. Such quasipartcles are also confined to a deep-subwavelength volumes [45]. Intriguingly, the near-equidistant space-coiling meta-structure of the spoof-plasmon device can be tailored into arbitrary shapes, demonstrating flexible skyrmionic textures robust with arbitrary shapes (Fig.…”

“…Dynamics of such skyrmionic SPP standing wave can be observed using photoemission electron microscopy [44]. Spoof localized SPP were also reported to generate skyrmion-like structures for the fields in a coiled metal films or metallic multifold structure acting as a resonator [45,46] but the topological protection needs to be further investigated. SPP field-skyrmions have the topological texture limited to Néel-type topology.…”

“…j, The skyrmion textures observed in the momentum space of a photonic crystal slab [74]. k, Topologically robust skyrmions with customized geometry generated on a structured localized spoof plasmons supported by ultrathin space-coiling meta-structures [45]. l, The 3D polarization texture of the vector beam representing an optical hopfion, where each Hopf fiber is constructed by a trajectory of a certain polarization ellipse (The hue colors depict different ellipse azimuths and dark to bright progression corresponds to the polarisation variation from left-to right-handed circular state) [75].…”

Topological Engineering of the Iso-Frequency Contours in Connection-Type Metamaterials

“…It would be highly desirable if the shapes of low-frequency IFSs can be customized at will, then we could control the EM wave propagation behavior in a relatively broader bandwidth. It is well known that metallic wire medium [4,[23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40], such as disconnected wire arrays, can exhibit the strong spatial dispersion (nonlocal effect) even in long-wavelength limit [25,26]. By incorporating two or more sets of metallic meshes, one can engineer the density of states at quasistatic limit [28,32,33].…”

“…Interestingly, researchers [33] found that the global connectivity of these metallic meshes can introduce a momentum shift of the low-frequency index ellipsoid away from the zero k-point. Recently, wire medium again attracted the attention of researchers, since it could serve as a new design degree of freedom to tailor the low-frequency dispersion [34][35][36][37] and associated wave properties [38][39][40] of MMs.…”