Defrance F, Casaletti M, Sarrazin J, Wiedner M C, Gibson H, Gay G, Lefèvre R, Delorme Y
Opt Express. 2016 Sep 5;24(18):20335-45. doi: 10.1364/OE.24.020335.
An iterative alternate projection-based algorithm is developed to design structured surface reflectors to operate as beam splitters at GHz and THz frequencies. To validate the method, a surface profile is determined to achieve a reflector at 610 GHz that generates four equal-intensity beams towards desired directions of ±12.6° with respect to the specular reflection axis. A prototype is fabricated and the beam splitter behavior is experimentally demonstrated. Measurements confirm a good agreement (within 1%) with computer simulations using Feko, validating the method. The beam splitter at 610 GHz has a measured efficiency of 78% under oblique incidence illumination that ensures a similar intensity between the four reflected beams (variation of about 1%).
开发了一种基于迭代交替投影的算法，用于设计在吉赫兹和太赫兹频率下用作分束器的结构化表面反射器。为了验证该方法，确定了一种表面轮廓，以实现一个在610吉赫兹的反射器，该反射器相对于镜面反射轴朝着±12.6°的期望方向生成四束等强度光束。制作了一个原型，并通过实验证明了分束器的性能。测量结果证实与使用Feko进行的计算机模拟具有良好的一致性（在1%以内），从而验证了该方法。610吉赫兹的分束器在斜入射照明下的测量效率为78%，确保了四束反射光束之间的强度相似（变化约1%）。
