紫外全息凹面光栅离子束刻蚀技术

通过对引出的平行离子柬流外加可控磁场，可以实现离子束流偏转。该方法实现IV型凹面光栅沿曲面不同闪耀角离子束刻蚀，能够获得高衍射效率的IV型凹面光栅。经过理论设计计算出理想的IV型凹面光栅闪耀角，利用全息曝光一弯转离子束刻蚀工艺制作出尺寸45mm×40mm，波长250nm处衍射效率达67％，入臂200mm，出臂188mm，曲率半径224mm的IV型凹面光栅。同时，利用平行离子束流制作了相同参数的IV型凹面光栅，其250nm处的衍射效率为30％。实验结果表明，利用弯转离子束流制作IV型凹面光栅的方法简单易行，并能够精确控制离子束流实现高衍射效率的IV型凹面光栅制作。

Ion beam etching of ultraviolet concave grating

The adjustable magnetic field is added to the parallel ion beam to realize the beam deflection, by which high diffraction efficiency IV-type concave grating can be obtained by ion bean etching at different blaze angles along the IV-type concave surface. The optimal blaze angle is calculated, and the IV-type concave grating is get with the holographic ion beam etching, grating size is 45 mmX 40 mm; diffraction efficiency 67% at 250 nm; input arm 200 mm; output arm188mm and curvature radius 224 mm. The same IV-type concave grating is made with parallel ion beam, and the diffraction efficiency is about 37% at 250 nm. The experimental results demonstrate that curing ion beam itching method is feasible, and the ion beam can be controlled to realized the fabrication of IV concave grating with high diffraction efficiency.