Grating-induced omnidirectional refraction of self-collimated beams at a photonic crystal surface

We report that self-collimated beams from a photonic crystal can be refracted to any direction in air by introducing an additional layer composed of dielectric rods at a photonic crystal surface. The refraction angle can be tuned from negative to positive value by adjusting the period of the additional layer. The refracted beam power can be also controllable by varying the radii of rods in the layer and the distance between the layer and the surface. The grating-induced omnidirectional refraction of self-collimated beams could provide an efficient way to manipulate light propagation and increase the possibility of application of self-collimated beams.