Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Topological near fields generated by topological structures   The central idea of metamaterials and metaoptics is that, besides their base
materials, the geometry of structures offers a broad extra dimension to explore
for exotic functionalities. Here, we discover that the topology of structures
fundamentally dictates the topological properties of optical near fields and
offers a new dimension to exploit for optical functionalities that are
irrelevant to specific material constituents or structural geometries. We find
that the nontrivial topology of metal structures ensures the birth of
polarization singularities (PSs) in the near field with rich morphologies and
intriguing spatial evolutions including merging, bifurcation, and topological
transition. By mapping the PSs to non-Hermitian exceptional points and
employing homotopy theory, we extract the core invariant that governs the
topological classification of the PSs and the conservation law that regulates
their spatial evolutions. The results have effectively bridged three vibrant
fields of singular optics, topological photonics, and non-Hermitian physics,
with potential applications in chiral sensing, chiral quantum optics, and
beyond photonics in other wave systems.

9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
22
The categories of this paper are: chao-dyn
2
The categories of this paper are: math
33
The categories of this paper are: plasm-ph
8
The categories of this paper are: hep-ex
31
The categories of this paper are: ao-sci
5
The categories of this paper are: gr-qc
15
The categories of this paper are: nucl-ex
26
The categories of this paper are: bayes-an
17
The categories of this paper are: q-fin
37
The categories of this paper are: supr-con
14
The categories of this paper are: math-ph
6
The categories of this paper are: astro-ph
24
The categories of this paper are: dg-ga