Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Vortex dynamics and applications to gaseous optical elements   Experimental studies of the optical properties of compressible, viscous and
rapidly-rotating gas flows (vortices) are presented. Gas vortices can function
as optical elements such as lenses or waveguides. The optical properties are
determined from direct interferometric phase measurements and beam propagation
analysis. Output beams are analyzed in terms of Zernike polynomials for a range
of gas flow parameters, including choked flow. The absolute radial gas density
distribution is measured and a technique for adjusting it is demonstrated.

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The categories of this paper are: gr-qc
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga
2
The categories of this paper are: math
27
The categories of this paper are: comp-gas
34
The categories of this paper are: chem-ph
0
The categories of this paper are: hep-ph
26
The categories of this paper are: bayes-an
32
The categories of this paper are: atom-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
31
The categories of this paper are: ao-sci
33
The categories of this paper are: plasm-ph
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg