Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dirac-vortex topological photonic crystal fibre   The success of photonic crystal fibres relies largely on the endless variety
of two-dimensional photonic crystals in the cross-section. Here, we propose a
topological bandgap fibre whose bandgaps along in-plane directions are opened
by generalized Kekul\'e modulation of a Dirac lattice with a vortex phase.
Then, the existence of mid-gap defect modes is guaranteed to guide light at the
core of this Dirac-vortex fibre, where the number of guiding modes equals the
winding number of the spatial vortex. The single-vortex design provides a
single-polarization single mode for a bandwidth as large as one octave.

29
The categories of this paper are: funct-an
14
The categories of this paper are: math-ph
2
The categories of this paper are: math
8
The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
0
The categories of this paper are: hep-ph
23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th
20
The categories of this paper are: acc-phys
5
The categories of this paper are: gr-qc
32
The categories of this paper are: atom-ph
34
The categories of this paper are: chem-ph
24
The categories of this paper are: dg-ga
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas