Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Resonant field enhancement near bound states in the continuum on
  periodic structures   On periodic structures sandwiched between two homogeneous media, a bound
state in the continuum (BIC) is a guided Bloch mode with a frequency within the
radiation continuum. BICs are useful, since they give rise to high
quality-factor ($Q$-factor) resonances that enhance local fields for
diffraction problems with given incident waves. For any BIC on a periodic
structure, there is always a surrounding family of resonant modes with
$Q$-factors approaching infinity. We analyze field enhancement around BICs
using analytic and numerical methods. Based on a perturbation method, we show
that field enhancement is proportional to the square-root of the $Q$-factor,
and it depends on the adjoint resonant mode and its coupling efficiency with
incident waves. Numerical results are presented to show different asymptotic
relations between the field enhancement and the Bloch wavevector for different
BICs. Our study provides a useful guideline for applications relying on
resonant enhancement of local fields.

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The categories of this paper are: hep-th
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The categories of this paper are: econ
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The categories of this paper are: hep-lat
25
The categories of this paper are: patt-sol
12
The categories of this paper are: nucl-th
4
The categories of this paper are: cond-mat
36
The categories of this paper are: cmp-lg
20
The categories of this paper are: acc-phys
24
The categories of this paper are: dg-ga
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
23
The categories of this paper are: solv-int
35
The categories of this paper are: mtrl-th
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The categories of this paper are: q-fin
31
The categories of this paper are: ao-sci
22
The categories of this paper are: chao-dyn