Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Polarization pattern of vector vortex beams generated by $q$-plates with
  different topological charges   We describe the polarization topology of the vector beams emerging from a
patterned birefringent liquid crystal plate with a topological charge $q$ at
its center ($q$-plate). The polarization topological structures for different
$q$-plates and different input polarization states have been studied
experimentally by measuring the Stokes parameters point-by-point in the beam
transverse plane. Furthermore, we used a tuned $q=1/2$-plate to generate
cylindrical vector beams with radial or azimuthal polarizations, with the
possibility of switching dynamically between these two cases by simply changing
the linear polarization of the input beam.

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The categories of this paper are: acc-phys
4
The categories of this paper are: cond-mat
27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci
34
The categories of this paper are: chem-ph
22
The categories of this paper are: chao-dyn
6
The categories of this paper are: astro-ph
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The categories of this paper are: solv-int
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The categories of this paper are: plasm-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: mtrl-th
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The categories of this paper are: patt-sol
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The categories of this paper are: bayes-an
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The categories of this paper are: math
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The categories of this paper are: stat
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The categories of this paper are: funct-an