基于解析分区法设计闪耀全息凹面光栅

Design of diffraction blazed concave grating by partitioned space calculated method

研究了制备闪耀凹面光栅的离子束刻蚀工艺,提出了用"解析分区法"设计闪耀凹面光栅的衍射效率。该方法能通过确定离子束入射角,在实验前定量给出平行离子束刻蚀后光栅衍射效率的设计结果。经过理论设计计算出所需波长衍射效率较高的凹面闪耀光栅中心闪耀角,利用刻蚀模拟软件BLAZING计算出离子束刻蚀参数及光刻胶掩模参数;以计算结果为依据,利用全息-离子束刻蚀工艺制作出尺寸为45 mm×40 mm2,曲率半径为224 mm的凹面闪耀光栅,其中心闪耀角约为9.21°,峰值衍射效率为54.8%@300 nm,250 nm处衍射效率为50%,与"解析分区法"计算结果符合较好。实验结果表明,利用"解析分区法"进行凹面闪耀光栅衍射效率设计的方法简单易行,能够有效指导平行离子束刻蚀闪耀凹面光栅工艺,完成高衍射效率凹面闪耀光栅的制作。

Ion beam etching technology was researched for fabricating blaze concave gratings, and a partitioned space calculated method was proposed to calculate the diffraction efficiency of a blaze con- cave grating. The method can calculate the diffraction efficiency quantitatively without experimenta- tion by confirming an incidence angle. The blazed angle of the blaze concave grating with a given wavelength was calculated based on the partitioned space calculated method, and ion beam etching pa- rameters and a mask parameter were calculated by etching software BLAZING. On the basis of these parameters, a concave grating with a size of 45mm X 40mm was fabricated by holographic ion beametching. The focus blazed angles measured by an Atomic Force Microscope（AFM） are 9.21~,the effi- cieneies of the gratings measured by a concave grating diffraction efficiency instrument are about 54. 8% at 300 nm and 50% at 250 nm. The grating substrate has a smooth blazed groove profile with 1 200 groove/mm. The results are in agreement with that partitioned space calculated well. It means that par- titioned space calculated method is suitable for designing and calculating the efficiency of blaze concave grat- ings and it can direct the fabrication of the blaze concave gratings by the ion beam etching technology.