Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Sculptured Thin Films: Accomplishments and Emerging Uses   Sculptured thin films (STFs) are nano-engineered materials whose columnar
morphology is tailored to elicit desired optical responses upon excitation. Two
canonical forms of STFs have been identified. Linear constitutive relations for
general STFs as unidirectionally nonhomogeneous (continuously or piecewise
uniformly) and locally bianisotropic continuums are presented, along with a
4$\times$4 matrix ordinary differential equation for wave propagation therein.
A nominal model for the macroscopic properties of linear STFs is devised from
nanoscopic considerations. The accomplished implementation of STFs as circular
polarization filters and spectral hole filters is discussed, as also are
emerging applications such as bioluminescence sensors and optical
interconnects.

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The categories of this paper are: q-bio
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The categories of this paper are: astro-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: q-fin
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The categories of this paper are: supr-con
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The categories of this paper are: dg-ga
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The categories of this paper are: math
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The categories of this paper are: alg-geom
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The categories of this paper are: nucl-ex
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The categories of this paper are: econ
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The categories of this paper are: quant-ph
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The categories of this paper are: math-ph
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The categories of this paper are: adap-org
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The categories of this paper are: cs
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The categories of this paper are: ao-sci
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The categories of this paper are: mtrl-th