For diffraction in the forward region, at large z and not very far from the z axis, the diffraction is the same in the two cases. To determine the form of the waves in the region z>0 (beyond the...For diffraction in the forward region, at large z and not very far from the z axis, the diffraction is the same in the two cases. To determine the form of the waves in the region z>0 (beyond the barrier), we need boundary conditions both at z=0 and at z=∞. 4 At z=∞, we must impose the condition that there are no waves traveling in the −z direction (back toward the barrier) and that the sodwlutions are well behaved at ∞.
