Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Complete bandgaps in one-dimensional left-handed periodic structures   Artificially fabricated structures with periodically modulated parameters
such as photonic crystals offer novel ways of controlling the flow of light due
to the existence of a range of forbidden frequencies associated with a photonic
bandgap. It is believed that modulation of the refractive index in all three
spatial dimensions is required to open a complete bandgap and prevent the
propagation of electromagnetic waves in all directions. Here we reveal that, in
a sharp contrast to what was known before and contrary to the accepted physical
intuition, a one-dimensional periodic structure containing the layers of
transparent left-handed (or negative-index) metamaterial can trap light in
three-dimensional space due to the existence of a complete bandgap.

9
The categories of this paper are: nlin
0
The categories of this paper are: hep-ph
15
The categories of this paper are: nucl-ex
19
The categories of this paper are: eess
16
The categories of this paper are: stat
33
The categories of this paper are: plasm-ph
2
The categories of this paper are: math
12
The categories of this paper are: nucl-th
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
30
The categories of this paper are: q-alg
6
The categories of this paper are: astro-ph
8
The categories of this paper are: hep-ex
24
The categories of this paper are: dg-ga
14
The categories of this paper are: math-ph
11
The categories of this paper are: hep-lat