Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Metallic helix array as a broadband wave plate   This study proposes that a metallic helix array can operate as a
highly-transparent broadband wave plate in propagation directions perpendicular
to the axis of helices. The functionality arises from a special property of the
helix array, namely that the eigenstates of elliptically right-handed and
left-handed polarization are dominated by Bragg scattering and local resonance
respectively, and can be modulated separately with nearly fixed difference
between their wavevectors in a wide frequency range. The wave plate
functionality is theoretically and experimentally demonstrated by the
transformation of polarized states in a wide frequency range.

4
The categories of this paper are: cond-mat
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The categories of this paper are: chao-dyn
10
The categories of this paper are: q-bio
11
The categories of this paper are: hep-lat
35
The categories of this paper are: mtrl-th
29
The categories of this paper are: funct-an
25
The categories of this paper are: patt-sol
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The categories of this paper are: gr-qc
28
The categories of this paper are: alg-geom
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The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
37
The categories of this paper are: supr-con
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The categories of this paper are: acc-phys
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The categories of this paper are: eess
36
The categories of this paper are: cmp-lg
2
The categories of this paper are: math