利用严格模式理论分析光栅透镜的衍射特性

光栅透镜因其独特的光学性能而具有广泛的应用.根据光栅透镜的线宽和间距微小渐变的特点,建立了光栅透镜的物理模型,并利用严格模式理论对其衍射特性进行分析.该方法物理概念清晰、公式简洁.对光栅透镜实现谐波分离、聚焦功能时的衍射效率与槽深关系的计算结果表明,其计算速度快、数值计算结果准确可靠.并对加工误差的影响进行了模拟计算,说明了在当前的微细加工的工艺水平条件下,能够制作出满足ICF系统要求的光栅透镜.实验上制作了尺寸为100 mm的大面积光栅透镜,其衍射效率的实验测试结果与理论计算结果一致.

Analysis of Diffractive Properties of Grating Lens by Using Rigorous Model Theory

Grating lenses have been widely applied to various optical system because of their special optical characteristics. Theoretically, the grating lens is subdivided into smaller sub-areas in this paper, and every sub-area is regarded as periodic micro-structure, according to lightly variance of adjacent linewidth. Rigorous modal theory is used for analyzing their diffractive properties in sequence, and finally total diffractive efficiency of grating lenses can be easily obtained. Numerical simulation is performed to calculate diffractive efficiency of grating lens, which is used for beam sampling and harmonic separation in high energy laser system. It shows that results computed by the method in this paper are accurate and valid. In addition, fabrication-process-tolerance effects on diffractive efficiency are also discussed. In experiment, a beam sampling grating with diameter 100 mm was fabricated, and its experimental diffractive efficiency is consistent with result calculated by the method in this paper.