  The polarization of light is utilized in many technologies throughout science
and engineering. The ability to transform one state of polarization to another
is a key enabling technology. Common polarization transformers are simple
polarizers and polarization rotators. Simple polarizers change the intensity
depending on the input state and can only output a fixed polarized state, while
polarization rotators rotates the input Stokes vector in the 3D Stokes space.
We experimentally demonstrate an all-optical input-agnostic polarization
transformer (AI-APT), which transforms all input states of polarization to a
particular state that can be polarized or partially polarized. The output state
of polarization and intensity depends solely on setup parameters, and not on
the input state, thereby the AI-APT functions differently from simple
polarizers and polarization rotators. The AI-APT is completely passive, and
thus can be used as a polarization controller or stabilizer for single photons
and ultrafast pulses. To achieve this, we, for the first time, experimentally
realize complete kinematic state controllability of an open single-qubit by
Kraus maps put forth in [Wu et al. J. Phys. A 40, 5681 (2007)]. The AI-APT may
open a new frontier of partially polarized ultrafast optics.
