Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Terahertz lasers based on optically pumped multiple graphene structures
  with slot-line and dielectric waveguides   Terahertz (THz) lasers on optically pumped multiple-graphene-layer (MGL)
structures as their active region are proposed and evaluated. The developed
device model accounts for the interband and intraband transitions in the
degenerate electron-hole plasma generated by optical radiation in the MGL
structure and the losses in the slot or dielectric waveguide. The THz laser
gain and the conditions of THz lasing are found. It is shown that the lasers
under consideration can operate at frequencies > 1 THz at room temperatures.

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The categories of this paper are: quant-ph
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The categories of this paper are: eess
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The categories of this paper are: adap-org
32
The categories of this paper are: atom-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: dg-ga
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The categories of this paper are: econ
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The categories of this paper are: astro-ph
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The categories of this paper are: hep-ph
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The categories of this paper are: math
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The categories of this paper are: nucl-th
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The categories of this paper are: funct-an
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The categories of this paper are: bayes-an
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The categories of this paper are: hep-ex
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The categories of this paper are: q-alg
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The categories of this paper are: plasm-ph