Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Competition between extinction and enhancement in surface enhanced Raman
  spectroscopy   Conjugated metallic nanoparticles are a promising means to achieve
ultrasensitive and multiplexed sensing in intact three-dimensional samples,
especially for biological applications, via surface enhanced Raman scattering
(SERS). We show that enhancement and extinction are linked and compete in a
collection of metallic nanoparticles. Counterintuitively, the Raman signal
vanishes when nanoparticles are excited at their plasmon resonance, while
increasing nanoparticle concentrations at off-resonance excitation sometimes
leads to decreased signal. We develop an effective medium theory that explains
both phenomena. Optimal choices of excitation wavelength, individual particle
enhancement factor and concentrations are indicated.

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The categories of this paper are: adap-org
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The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
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The categories of this paper are: solv-int
14
The categories of this paper are: math-ph
22
The categories of this paper are: chao-dyn
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The categories of this paper are: dg-ga
12
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: cmp-lg
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The categories of this paper are: supr-con
10
The categories of this paper are: q-bio
33
The categories of this paper are: plasm-ph
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The categories of this paper are: astro-ph
2
The categories of this paper are: math
17
The categories of this paper are: q-fin