Bengtsson J, Eriksson N, Larsson A
Appl Opt. 1996 Feb 10;35(5):801-6. doi: 10.1364/AO.35.000801.
A binary fan-out kinoform for focusing and splitting an incident beam into a 4 × 4 spot array, with a largest deflection angle of 28°, was designed, fabricated in GaAs, and evaluated. The kinoform was defined in resist with electron-beam lithography and etched into GaAs with chemically assisted ion-beam etching. Light at wavelength 0.98 µm from a single-mode fiber was used to illuminate the kinoform. The efficiency was measured to be 34%, and the uniformity error for the 4×4 spots was 29%. Although the typical feature size of the kinoform is only roughly two wavelengths, we found that the scalar theory of diffraction can be used. A first kinoform was designed with the customary Fresnel-diffraction theory, which was found to be too coarse, resulting in a fan-out exhibiting some distortion. A second kinoform was designed with the more rigorous Fresnel-Kirchhoff expression, and its fan-out shows no distortion.
设计、制作并评估了一种用于将入射光束聚焦并分裂成4×4光斑阵列的二元扇出型相息图，其最大偏转角为28°。该相息图采用电子束光刻技术在光刻胶中定义，并通过化学辅助离子束蚀刻工艺蚀刻到砷化镓中。使用来自单模光纤的波长为0.98 µm的光照射该相息图。测量得到的效率为34%，4×4光斑的均匀性误差为29%。尽管相息图的典型特征尺寸仅约为两个波长，但我们发现可以使用标量衍射理论。第一个相息图采用传统的菲涅耳衍射理论设计，结果发现过于粗糙，导致扇出出现一些失真。第二个相息图采用更严格的菲涅耳 - 基尔霍夫表达式设计，其扇出没有失真。
