Coherent continuum phase matching
= Coherent continuum phase matching
In a homogeneous medium driven by a <plane wave>, coherent scattering amplitudes carry phases $e^{i(\mathbf k_i-\mathbf k_s)\cdot\mathbf r}$. An infinite uniform volume cancels arbitrary nonforward components. Finite shapes, boundaries and fluctuations determine any side signal; summing independent-particle intensities is not the continuous-medium limit.