Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Sub 200fs pulse generation from a graphene mode-locked fiber laser   Ultrafast fiber lasers with short pulses and broad bandwidth are in great
demand for a variety of applications, such as spectroscopy, biomedical
diagnosis and optical communications. In particular sub-200fs pulses are
required for ultrafast spectroscopy with high temporal resolution. Graphene is
an ideal ultra-wide-band saturable absorber. We report the generation of 174fs
pulses from a graphene-based fiber laser

26
The categories of this paper are: bayes-an
2
The categories of this paper are: math
17
The categories of this paper are: q-fin
36
The categories of this paper are: cmp-lg
28
The categories of this paper are: alg-geom
20
The categories of this paper are: acc-phys
22
The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci
29
The categories of this paper are: funct-an
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The categories of this paper are: comp-gas
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The categories of this paper are: patt-sol
23
The categories of this paper are: solv-int
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The categories of this paper are: plasm-ph
35
The categories of this paper are: mtrl-th
14
The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph