Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Generation of correlated photons in hydrogenated amorphous-silicon
  waveguides   We report the first (to our knowledge) observation of correlated photon
emission in hydrogenated amorphous- silicon waveguides. We compare this to
photon generation in crystalline silicon waveguides with the same geome- try.
In particular, we show that amorphous silicon has a higher nonlinearity and
competes with crystalline silicon in spite of higher loss.

29
The categories of this paper are: funct-an
7
The categories of this paper are: hep-th
18
The categories of this paper are: econ
37
The categories of this paper are: supr-con
19
The categories of this paper are: eess
0
The categories of this paper are: hep-ph
32
The categories of this paper are: atom-ph
12
The categories of this paper are: nucl-th
22
The categories of this paper are: chao-dyn
34
The categories of this paper are: chem-ph
21
The categories of this paper are: adap-org
35
The categories of this paper are: mtrl-th
11
The categories of this paper are: hep-lat
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
5
The categories of this paper are: gr-qc