Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Imaging spatio-temporal Hong-Ou-Mandel interference of bi-photon state
  of extremely high Schmidt number   We report the experimental observation of a spatio-temporal Hong-Ou-Mandel
(HOM) interference of bi-photon states of extremely high Schmidt number.
Two-photon interference of 1500 spatial modes and a total of more than 3x10^6
spatio-temporal modes is evidenced by measuring momentum spatial coincidences
between the pixels of the far-field images of two strongly multimode
spontaneous parametric down conversion (SPDC) beams propagating through a HOM
interferometer. The outgoing SPDC beams are recorded onto two separate
detectors arrays operating in the photon-counting regime. The properties of HOM
interference are investigated both in the time and space domains. We show that
the two-photon interferences exhibit temporal and two-dimensional spatial HOM
dips with visibilities of 30% and widths in good agreement with the
spatio-temporal coherence properties of the bi-photon state. Moreover, we
demonstrate that a peak of momentum spatial coincidences is evidenced inside
each image, in correspondence with this dip.

17
The categories of this paper are: q-fin
12
The categories of this paper are: nucl-th
5
The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th
27
The categories of this paper are: comp-gas
14
The categories of this paper are: math-ph
18
The categories of this paper are: econ
29
The categories of this paper are: funct-an
23
The categories of this paper are: solv-int
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The categories of this paper are: nlin
37
The categories of this paper are: supr-con
2
The categories of this paper are: math
33
The categories of this paper are: plasm-ph
6
The categories of this paper are: astro-ph
30
The categories of this paper are: q-alg
26
The categories of this paper are: bayes-an