  Zak phase, i.e. the Berry phase acquired during an adiabatic motion of a
Bloch particle across the Brillouin zone, provides a measure of the topological
invariant of Bloch bands in one-dimensional crystalline potentials. Here a
photonic structure, based on engineered lattices of evanescently-coupled
optical waveguides, is proposed to detect Zak phase difference of photons
undergoing Bloch oscillations in topologically distinct Bloch bands of
dimerized superlattices.
