  The optical modes of photonic structures are the so-called TE and TM modes
which bring intrinsic spin-orbit coupling and chirality to these systems. This,
combined with the unique flexibility of design of the photonic potential, and
the possibility to mix photon states with excitonic resonances, sensitive to
magnetic field and interactions, allows to achieve many phenomena, often
analogous to other solid state systems. In this contribution, we review in a
qualitative and comprehensive way several of these realizations, namely the
optical spin Hall effect, the creation of spin currents protected by a
non-trivial geometry, Berry curvature for photons, and the photonic/polaritonic
topological insulator.
