  Periodic structures resonantly coupled to excitonic media allow the existence
of extra intragap modes ('Braggoritons'), due to the coupling between Bragg
photon modes and 3D bulk excitons. This induces unique and unexplored
dispersive features, which can be tailored by properly designing the photonic
bandgap around the exciton resonance. We report that one-dimensional
Braggoritons realized with semiconductor gratings have the ability to mimic the
dispersion of quantum-well microcavity polaritons. This will allow the
observation of new nonlinear phenomena, such as slow-light-enhanced nonlinear
propagation and an efficient parametric scattering at two 'magic frequencies'.
