Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Symmetry breaking of optical vortices: Birth and annihilation of
  singularities in the evanescent field   The interaction of optical vortices (or phase singularities, screw
dislocations) with ordinary matter is treated with simple approach. Using total
internal reflection phenomenon and superposition of four plane waves incident
on a material with refractive index lower than the original propagating medium,
we are able to show birth and annihilation of optical vortices in the
evanescent field with curved topological features. Until now, this phenomenon
has been explored only in free space propagation. By a suitable tuning process,
involving the incident angles and the amplitudes of the incident plane waves,
it is possible to create unusual topological features of optical vortices in
the vicinity of the material. We believe that this work can open new aspects of
curved optical vortex manipulation in near-field optics.

25
The categories of this paper are: patt-sol
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg
15
The categories of this paper are: nucl-ex
10
The categories of this paper are: q-bio
26
The categories of this paper are: bayes-an
6
The categories of this paper are: astro-ph
31
The categories of this paper are: ao-sci
13
The categories of this paper are: quant-ph
14
The categories of this paper are: math-ph
28
The categories of this paper are: alg-geom
32
The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
29
The categories of this paper are: funct-an
1
The categories of this paper are: cs
5
The categories of this paper are: gr-qc