Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Generation of pure-state single photons with high heralding efficiency
  by using a three-stage nonlinear interferometer   We experimentally study a fiber-based three-stage nonlinear interferometer
and demonstrate its application in generating heralded single photons with high
efficiency and purity by spectral engineering. We obtain a heralding efficiency
of 90% at a brightness of 0.039 photons/pulse. The purity of the source is
checked by two-photon Hong-Ou-Mandel interference with a visibility of 95%+-6%
(after correcting Raman scattering and multi-pair events). Our investigation
indicates that the heralded source of single photons produced by the
three-stage nonlinear interferometer has the advantages of high purity, high
heralding efficiency, high brightness, and flexibility in wavelength and
bandwidth selection.

14
The categories of this paper are: math-ph
1
The categories of this paper are: cs
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga
12
The categories of this paper are: nucl-th
36
The categories of this paper are: cmp-lg
2
The categories of this paper are: math
30
The categories of this paper are: q-alg
34
The categories of this paper are: chem-ph
33
The categories of this paper are: plasm-ph
26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th
6
The categories of this paper are: astro-ph
25
The categories of this paper are: patt-sol
16
The categories of this paper are: stat
7
The categories of this paper are: hep-th