Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ienversionless gain in an optically-dense resonant Doppler-broadened
  medium   Resonant nonlinear-optical interference processes in four-level
Doppler-broadened media are studied. Specific features of amplification and
optical switching of short-wavelength radiation in a strongly-absorbing
resonant gas under coherent quantum control with two longer wavelength
radiations, are investigated. The major outcomes are illustrated with virtual
experiments aimed at inversionless short-wavelength amplification, which also
address deficiencies in this regard in recent experiments. With numerical
simulations related to the proposed experiment in optically-dense sodium dimer
vapor, we show optimal condition for optical switching and the expected gain of
the probe radiation, which is above the oscillation threshold.

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The categories of this paper are: math
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The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
15
The categories of this paper are: nucl-ex
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The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga
21
The categories of this paper are: adap-org
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The categories of this paper are: astro-ph
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The categories of this paper are: cs
20
The categories of this paper are: acc-phys
9
The categories of this paper are: nlin
17
The categories of this paper are: q-fin
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
18
The categories of this paper are: econ
25
The categories of this paper are: patt-sol