  Multiple photon addition and subtraction applied to multi-mode thermal and
sub-Poissonian fields as well as twin beams is mutually compared using one
experimental setup. Twin beams with tight spatial correlations detected by an
intensified CCD camera with high spatial resolution are used to prepare the
initial fields. Up to three photons are added or subtracted to arrive at the
nonclassical and non-Gaussian states. Only the photon-subtracted thermal states
remain classical. In general, the experimental photon-added states exhibit
greater nonclassicality and non-Gaussianity than the comparable
photon-subtracted states. Once photons are added or subtracted in twin beams,
both processes result in comparable properties of the obtained states owing to
twin-beam photon pairing.
