Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Backpropagation Imaging in Nonlinear Harmonic Holography in the Presence
  of Measurement and Medium Noises   In this paper, the detection of a small reflector in a randomly heterogenous
medium using second-harmonic generation is investigated. The medium is
illuminated by a time-harmonic plane wave at frequency omega. It is assumed
that the reflector has a non-zero second-order nonlinear susceptibility, and
thus emits a wave at frequency two omega in addition to the fundamental
frequency linear scattering. It is shown how the fundamental frequency signal
and the second-harmonic signal propagate in the medium. A statistical study of
the images obtained by migrating the boundary data is performed. It is proved
that the second-harmonic image is more stable with respect to medium noise than
the one obtained with the fundamental signal. Moreover, the signal-to-noise
ratio for the second-harmonic image does not depend neither on the second-order
susceptibility tensor nor on the volume of the particle.

10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
23
The categories of this paper are: solv-int
17
The categories of this paper are: q-fin
7
The categories of this paper are: hep-th
6
The categories of this paper are: astro-ph
18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph
14
The categories of this paper are: math-ph
31
The categories of this paper are: ao-sci
5
The categories of this paper are: gr-qc
36
The categories of this paper are: cmp-lg
20
The categories of this paper are: acc-phys
11
The categories of this paper are: hep-lat
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The categories of this paper are: nucl-th
22
The categories of this paper are: chao-dyn