We experimentally characterize the positions of the diffraction maxima of a phase grating on a screen, for laser light at oblique incidence (so-called off-plane diffraction or conical diffraction). We discuss the general case of off-plane diffraction geometries and derive basic equations for the positions of the diffraction maxima, in particular for their angular dependence. In contrast to previously reported work (Jetty et al. in Am J Phys 80:972, 2012), our reasoning is solely based on energy- and momentum conservation. We find good agreement of our theoretical prediction with the experiment. A detailed discussion of the diffraction maxima positions, the number of diffraction orders, and the diffraction efficiencies is provided. We assess the feasibility of an experimental test of the phenomenon for neutron matter waves.

我们实验性地描述了屏幕上相位光栅最大衍射的位置，用于倾斜入射的激光（所谓的平面外衍射或圆锥形衍射）。我们讨论了平面外衍射几何的一般情况，并推导了衍射最大值位置的基本方程，尤其是它们的角度依赖性。与先前报道的工作（Jetty等人，Am J Phys 80：972，2012）相反，我们的推理仅基于能量和动量守恒。我们发现理论预测与实验相吻合。提供了有关衍射最大值位置，衍射级数和衍射效率的详细讨论。我们评估对中子物质波现象进行实验测试的可行性。