  The recently discovered ferroelectric nematic liquids incorporate to the
functional combination of fluidity, processability and anisotropic optical
properties of nematic liquids, an astonishing range of physical properties
derived from the phase polarity. Among them, the remarkably large values of
second order optical susceptibility encourage to exploit these new materials
for non-linear photonic applications. Here we show that photopatterning of the
alignment layer can be used to structure polarization patterns. To do so, we
take advantage of the flexoelectric effect and design splay structures that
geometrically define the polarization direction. We demonstrate the creation of
periodic polarization structures and the possibility of guiding polarization by
embedding splay structures in uniform backgrounds. The demonstrated
capabilities of polarization patterning, open a promising new route for the
design of ferroelectric nematic based photonic structures and their
exploitation.
