Negative refraction effect in two dimensional square and hexagonal photonic crystal

This paper demonstrates that light propagation in two dimensional square and hexagonal lattices photonic crystal (PhCs) behaves negative refraction effect in the vicinity of the photonic bandgaps. Plane wave expansion method was used to solve complex eigenvalue problems, as well as to plot dispersion curves and Equi-frequency surfaces (EFS). Theoretical simulating results have been presented, and all-angle negative refraction and superlensing effect have been versified.