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 \(z=\infty\). 4 At \(z=\infty\), 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 \(\infty\).
