Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Signature of a three-dimensional photonic band gap observed on silicon
  inverse woodpile photonic crystals   We have studied the reflectivity of CMOS-compatible three-dimensional silicon
inverse woodpile photonic crystals at near-infrared frequencies.
Polarization-resolved reflectivity spectra were obtained from two orthogonal
crystal surfaces corresponding to 1.88 pi sr solid angle. The spectra reveal
broad peaks with high reflectivity up to 67 % that are independent of the
spatial position on the crystals. The spectrally overlapping reflectivity peaks
for all directions and polarizations form the signature of a broad photonic
band gap with a relative bandwidth up to 16 %. This signature is supported with
stopgaps in plane wave bandstructure calculations and with the frequency region
of the expected band gap.

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The categories of this paper are: gr-qc
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The categories of this paper are: quant-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-lat
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The categories of this paper are: mtrl-th
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The categories of this paper are: comp-gas
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The categories of this paper are: cond-mat
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The categories of this paper are: funct-an
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The categories of this paper are: hep-th
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The categories of this paper are: solv-int
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The categories of this paper are: stat
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The categories of this paper are: acc-phys
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The categories of this paper are: alg-geom
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The categories of this paper are: dg-ga
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The categories of this paper are: supr-con
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The categories of this paper are: cmp-lg