A simple free-space optics recipe for the generation and detection of the optical vortices superposition is demonstrated. For the purpose a doughnut laser beam is produced by the cracked glass plate. To control the vorticity of produced doughnut light, one can deform the cracked plate. For the generation of the optical vortices superposition and determination the vorticity of the produced doughnut light, two simple interferometry setups are employed. The experimental Sagnac interferometry setup for preparing and analysing superpositions of an optical vortex and Gaussian modes is presented. Furthermore, the superpositions of two twisted beam with the opposite topological charge numbers by an experimental Michelson–Sagnac interferometry is proposed. These simple free-space experiments are useful to the application of orbital angular momenta superpositions in the quantum cryptography and the undergraduate educations

演示了用于生成和检测光学涡流叠加的简单自由空间光学配方。为此，破裂的玻璃板会产生环形激光束。为了控制产生的甜甜圈光的涡度，可以使破裂的板变形。为了产生光学涡流叠加和确定产生的甜甜圈光的涡度，采用了两个简单的干涉测量装置。介绍了用于准备和分析光学涡旋和高斯模式叠加的实验 Sagnac 干涉测量装置。此外，提出了通过实验迈克尔逊-萨格纳克干涉测量法叠加具有相反拓扑电荷数的两个扭曲光束。