Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Experimental demonstration of self-collimation beaming and splitting in
  photonic crystals   I studied experimentally the beam self-collimation and splitting in
two-dimensional microwave photonic crystals. Using a microwave photonic crystal
fabricated from alumina rods, I present an experimental proof of principle for
an earlier theoretical proposal [A. Matthews et al., Opt. Commun. 279, 313
(2007)] of a photonic crystal beam splitter based on the self-collimation
effect.

4
The categories of this paper are: cond-mat
7
The categories of this paper are: hep-th
15
The categories of this paper are: nucl-ex
16
The categories of this paper are: stat
28
The categories of this paper are: alg-geom
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
18
The categories of this paper are: econ
5
The categories of this paper are: gr-qc
14
The categories of this paper are: math-ph
17
The categories of this paper are: q-fin
23
The categories of this paper are: solv-int
34
The categories of this paper are: chem-ph
22
The categories of this paper are: chao-dyn
37
The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an