Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Light propagation control by finite-size effects in photonic crystals   We exhibit the strong influence on light propagation of the finite size in
photonic band-gap material. We show that light emission can be controlled by
the symmetry group of the boundary of the finite device. These results lead
simply to important practical applications.

5
The categories of this paper are: gr-qc
13
The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
23
The categories of this paper are: solv-int
33
The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
19
The categories of this paper are: eess
0
The categories of this paper are: hep-ph
27
The categories of this paper are: comp-gas
34
The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
18
The categories of this paper are: econ
17
The categories of this paper are: q-fin
11
The categories of this paper are: hep-lat
8
The categories of this paper are: hep-ex
10
The categories of this paper are: q-bio