Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Three Dimensional Photothermal Deflection of Solids Using Modulated CW
  Lasers : Theoretical Development   In this paper, a detailed theoretical treatment of the three dimensional
photothermal deflection, under modulated cw excitation, is presented for a
three layer system (backing-solid sample- fluid).By using a technique based on
Green's function and integral transformations we find the explicit expressions
for laser induced temperature distribution function and the photothermal
deflection of the probe beam. Numerical analysis of those expressions for
certain solid samples leads to some interesting results.

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The categories of this paper are: funct-an
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The categories of this paper are: eess
10
The categories of this paper are: q-bio
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The categories of this paper are: chem-ph
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The categories of this paper are: supr-con
14
The categories of this paper are: math-ph
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The categories of this paper are: dg-ga
8
The categories of this paper are: hep-ex
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The categories of this paper are: stat
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The categories of this paper are: solv-int
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The categories of this paper are: comp-gas
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-lat
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The categories of this paper are: hep-th
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The categories of this paper are: q-alg
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The categories of this paper are: q-fin