Diploma thesis

1 Overview
In the scope of this thesis, we theoretically and experimentally investigate the spatial
and spectral properties of three-wave mixing processes. We extend the theoretical
framework of waveguided parametric downconversion (PDC) to included different
spatial modes and evanescent waves in the surrounding material. We compare the
fidelity of different approaches to generate pure heralded single photon states. This
is an important prerequisite for further PDC experiments. To perform all these
calculations we developed a simulation which can deal with all needed formulas
to describe the PDC process and analyse the spectral correlations by a Schmidt
decomposition.
Different waveguide samples have been examined in the laboratory with second
harmonic generation (SHG). The gained information proved useful to construct further
experiments with these crystals. Additionally, this data yielded the possibility
to test the performance of the theoretical framework in comparison to experimental
data. Finally, we observed PDC photon pairs taking into account the measured
crystal properties.
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