Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Comparison of collimated blue light generation in ${}^{85}$Rb atoms via
  the D${}_1$ and D${}_2$ lines   We experimentally studied the characteristics of the collimated blue light
(CBL) produced in ${}^{85}$Rb vapor by two resonant laser fields exciting atoms
into the $5D_{3/2}$ state, using either the $5P_{1/2}$ or the $5P_{3/2}$
intermediate state. We compared the CBL output at different values of frequency
detunings, powers, and polarizations of the pump lasers in these two cases, and
confirmed the observed trends using a simple theoretical model. We also
demonstrated that the addition of the repump laser, preventing the accumulation
of atomic population in the uncoupled hyperfine ground state, resulted in
nearly an order of magnitude increase in CBL power output. Overall, we found
that the $5S_{1/2} - 5P_{1/2} - 5D_{3/2}$ excitation pathway results in
stronger CBL generation, as we detected up to $4.25~\mu$W using two pumps of
the same linear polarization. The optimum CBL output for the $5S_{1/2} -
5P_{3/2} - 5D_{3/2}$ excitation pathway required the two pump lasers to have
the same circular polarization, but resulted only in a maximum CBL power of
$450$~nW.

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The categories of this paper are: q-bio
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The categories of this paper are: math-ph
29
The categories of this paper are: funct-an
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The categories of this paper are: alg-geom
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The categories of this paper are: solv-int
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The categories of this paper are: gr-qc
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The categories of this paper are: bayes-an
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The categories of this paper are: comp-gas
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The categories of this paper are: supr-con
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The categories of this paper are: adap-org
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The categories of this paper are: eess
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The categories of this paper are: nucl-ex
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The categories of this paper are: q-alg
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The categories of this paper are: ao-sci
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The categories of this paper are: cmp-lg
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The categories of this paper are: math