Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Comparing focal plane wavefront control techniques:\\Numerical
  simulations and laboratory experiments   Fewer than 1% of all exoplanets detected to date have been characterized on
the basis of spectroscopic observations of their atmosphere. Unlike indirect
methods, high-contrast imaging offers access to atmospheric signatures by
separating the light of a faint off-axis source from that of its parent star.
Forthcoming space facilities, such as WFIRST/LUVOIR/HabEX, are expected to use
coronagraphic instruments capable of imaging and spectroscopy in order to
understand the physical properties of remote worlds. The primary technological
challenge that drives the design of these instruments involves the precision
control of wavefront phase and amplitude errors. Several FPWS and control
techniques have been proposed and demonstrated in laboratory to achieve the
required accuracy. However, these techniques have never been tested and
compared under the same laboratory conditions. This paper compares two of these
techniques in a closed loop in visible light: the pair-wise (PW) associated
with electric field conjugation (EFC) and self-coherent camera (SCC). We first
ran numerical simulations to optimize PW wavefront sensing and to predict the
performance of a coronagraphic instrument with PW associated to EFC wavefront
control, assuming modeling errors for both PW and EFC. Then we implemented the
techniques on a laboratory testbed. We introduced known aberrations into the
system and compared the wavefront sensing using both PW and SCC. The speckle
intensity in the coronagraphic image was then minimized using PW+EFC and SCC
independently. We demonstrate that both SCC and PW+EFC can generate a dark hole
in space-like conditions in a few iterations. Both techniques reach the current
limitation of our laboratory bench and provide coronagraphic contrast levels of
5e-9 in a narrow spectral band (<0.25% bandwidth)

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The categories of this paper are: hep-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: math-ph
35
The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
34
The categories of this paper are: chem-ph
16
The categories of this paper are: stat
17
The categories of this paper are: q-fin
26
The categories of this paper are: bayes-an
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The categories of this paper are: q-alg
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The categories of this paper are: acc-phys
18
The categories of this paper are: econ
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The categories of this paper are: adap-org
13
The categories of this paper are: quant-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: cond-mat