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    • 摘要: 激光雷达目前主要使用达曼光栅实现激光分束。然而,达曼光栅作为周期性衍射光学器件需要满足光栅方程,其各衍射角的正弦值成等差数列,无法实现均匀的角度分束,同时理论衍射效率受到限制。本文将角谱法和随机搜索算法结合,设计了一种非周期性红外超构表面激光分束器。该分束器可实现70°的分束全角等角度间隔的41分束。其理论衍射效率达84%,高于二元相位器件的理论极限。在实验测试中,超构表面分束器具有较好的分束均匀性,可促进激光雷达的发展。

       

      Abstract: LiDAR currently mainly uses a Dammann grating as the laser beamsplitter. However, as a periodic diffraction optical device, the Dammann grating satisfies the grating equation requiring each diffraction angle's sine value to form an arithmetic progression, which cannot achieve uniform angular beam-splitting. The theoretical diffraction efficiency is also limited. This paper uses the angular spectrum and random search optimization algorithm to design a more flexible non-periodic beamsplitter. Simulations show that the metasurface beamsplitter can achieve a 70-degree field angle of 41 beams with an equal diffraction angle interval. The simulated diffraction efficiency reaches 84% which is higher than the diffraction limit of a binary phase device. In experiments, the metasurface beamsplitter has good beam-splitting uniformity and can promote the development of LiDAR.