Abstract
We showed the two-dimensional THz photonic band gaps in calculations and experiments. Using the plane-wave expansion method, we have solved Maxwell's equations for the propagation of electromagnetic wave in a periodic lattice of dielectric rods in a uniform dielectric background. Choosing the proper dimension of the crystal, the photonic bands of square net, triangular, and graphite structure for THz radiation in a specific direction are calculated and drew. Using the THz electro-optics sampling method, we tested and verified the results of calculations with teflon structures. For triangular structure, the lowest complete photonic band gap is opened about 0.07THz. For graphite structure, the complete photonic gap is opened about 0.075THz.