Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Strongly anisotropic media: the THz perspectives of left-handed
  materials   We demonstrate that non-magnetic ($\mu \equiv 1$) left-handed materials can
be effectively used for waveguide imaging systems. We also propose a specific
THz realization of the non-magnetic left-handed material based on homogeneous,
naturally-occurring media.

6
The categories of this paper are: astro-ph
4
The categories of this paper are: cond-mat
27
The categories of this paper are: comp-gas
13
The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
10
The categories of this paper are: q-bio
11
The categories of this paper are: hep-lat
18
The categories of this paper are: econ
31
The categories of this paper are: ao-sci
2
The categories of this paper are: math
12
The categories of this paper are: nucl-th
7
The categories of this paper are: hep-th
17
The categories of this paper are: q-fin
0
The categories of this paper are: hep-ph
1
The categories of this paper are: cs
24
The categories of this paper are: dg-ga