  We present a broadband optical-conductivity study of superconducting
single-crystalline EuFe2(As1-xPx)2 with three different substitutional levels.
We analyze the normal-state electrodynamics by decomposing the conductivity
spectra using a Drude-Lorentz model with two Drude terms representing two
groups of carriers with different scattering rates. The analysis reveals that
the scattering rate of at least one of the Drude components develops linearly
with temperature for each doping level. This points towards strong
electron-electron correlations and a non-Fermi-liquid behavior in the
P-substituted superconducting Eu-122 pnictides. We also detect a transfer of
the spectral weight from mid-infrared to higher frequencies and assign it to
the Hund's-rule coupling between itinerant and localized carriers. The
conductivity spectra below the superconducting transition show no sharp
features to be associated with the dirty-limit superconducting BCS gaps. We
interpret these results in terms of clean-limit superconductivity in
EuFe2(As1-xPx)2. The best parametrization fit can be achieved using a two-gap
model. We find that the larger gap at the hole pockets of the Fermi surface is
likely to be isotropic, while the smaller gap at the electron pockets is
anisotropic or even nodal.
