Realization of Dirac point with double cones in optics.

The Dirac point (DP) with a double-cone structure for optical fields can be realized in optically homogenous media. The condition for the realization of DP in optical systems is the varying of refractive index from negative to zero and then to positive. Our analysis verify that, similar to electrons in graphene, the light field near DP possesses of the pseudodiffusive property obeying the 1/L scaling law, where L is the propagation distance inside the media.