为实现旋转双光楔二维扫描的可控操作，利用几何光学和光的标量衍射理论，对双光楔的折光特性进行了数学分析。研究发现：绕固定轴以不同角速度旋转的双光楔可等效为一个折射棱角和主截面都变化的单光楔。以该双光楔系统作为衍射屏，对通过双光楔的光束在观察面的衍射光场分布作了理论分析，得到了夫琅和费衍射下，光束经转动双光楔在像平面上的衍射光斑随转角变化的规律：光斑的横坐标与两光楔转角正弦值的差成正比，纵坐标与两光楔转角余弦值的和成正比。

A mathematic model for dual-wedge prism system is proposed to analyze the refractive property of light. By use of the theories of geometric optics and scalar diffraction, it is found that the dual-wedge prism can be simplified as a single-wedge prism whose angle between two refractive planes and main optical plane are changed with the rotary angle between two wedges. When these two wedges rotate in the different angle speed and opposite direction, the refractive light from this system is in two dimensions. Besides, taking the dual-wedge system as a diffractive screen, a theoretical analysis is made on the diffraction light field distribution of the beam which passes through the rotary dual-wedge system. Under the condition of Fraunhofer diffraction, the variation law of diffraction light spots with the rotary angle was obtained. This research may give a developing direction for the 2-D controllable scan.