Nature of the Poynting Vector Field Singularities in Resonant Light Scattering by Nanoparticles

能量流的拓扑结构：坡印廷矢量斯格明子

Topological structures of energy flow: Poynting vector skyrmions

该研究在反向传播柱矢量涡旋光束的焦区发现坡印廷矢量形成的斯格明子及其Néel–Bloch–Néel转变，并指出其类型可由相干叠加电磁场分量的相位奇点判定。

Polarization singularities on high index nanoparticles

In this article, we study the emergence of polarization singularities in the scattered fields of optical resonators excited by linearly polarized plane waves. First, we prove analytically that combinations of isotropic electric and magnetic dipoles can sustain L surfaces, and C lines that propagate from the near-field to the far field. Moreover, based on these analytical results, we derive anomalous scattering Kerker conditions trough singular optics arguments. Secondly, through exact full-field calculations, we demonstrate that high refractive index spherical resonators present such topologic…

Paraxial light in a Cole-Cole nonlocal medium: integrable regimes and singularities

Nonlocal nonlinear Schroedinger-type equation is derived as a model to describe paraxial light propagation in nonlinear media with different `degrees' of nonlocality. High frequency limit of this equation is studied under specific assumptions of Cole-Cole dispersion law and a slow dependence along propagating direction. Phase equations are integrable and they correspond to dispersionless limit of Veselov-Novikov hierarchy. Analysis of compatibility among intensity law (dependence of intensity on the refractive index) and high frequency limit of Poynting vector conservation law reveals the exis…

A novel all-dielectric optical micromixing device for lab-on-a-chip platforms

The exciting properties of high index dielectric nanoparticles exhibiting both electric and magnetic Mie resonances are nowadays paving the way towards efficient light manipulation at the nanoscale. A commonly disregarded peculiarity of light scattering by Mie particles is their ability to extract angular momentum from the incident electromagnetic field. In this work, we have investigated numerically and analytically the angular momentum transfer from a circularly polarized plane wave to the transversely scattered field generated by a high index cube. Therefore, the tangential components of th…

近场能量流拓扑重组调控亚波长矩形沟槽散射转变

Topological reorganization of near-field energy flow governing scattering transitions in subwavelength rectangular grooves

研究揭示亚波长矩形沟槽散射转变由近场能量流拓扑重组调控，通过分析电磁场与坡印廷矢量揭示能量传输重构机制。

Directional scattering from particles under evanescent wave illumination: the role of reactive power

Study of photonic spin-orbital interactions, which involves control of the propagation and spatial distributions of light with the polarization of electromagnetic fields, is not only important at the fundamental level but also has significant implications for functional photonic applications that require active tuning of directional light propagation. Many of the experimental demonstrations have been attributed to the spin-momentum locking characteristic of evanescent waves. In this letter, we show another property of evanescent waves: the polarization dependent direction of the imaginary part…

Supertoroidal light pulses: Propagating electromagnetic skyrmions in free space

Topological structures of electromagnetic fields could give access to nontrivial light-matter interactions and additional degrees of freedom for information and energy transfer. A characteristic example of such electromagnetic excitations are space-time non-separable single-cycle pulses, the exact solutions of Maxwell equation of toroidal topology predicted by Hellwarth and Nouchi in 1996 and recently observed experimentally. Here we introduce a new family of electromagnetic excitation of toroidal topology with increasing complexity in which the Hellwarth-Nouchi pulse is just the simplest memb…