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| 用介电质超表面产生准艾里光束 |
| Generation of quasi Airy beam using dielectric metasurface |
| 投稿时间：2020-11-13 |
| DOI：10.3969/j.issn.1005-5630.2021.02.001 |
| 中文关键词: 傅里叶变换 准艾里光束 介电质超表面 |
| 英文关键词:Fourier transform quasi Airy beam dielectric metasurface |
| 基金项目:国家重点研发计划（2018YFA0701800）；国家自然科学基金（81701745、61775140）；上海市科学技术委员会创新行动计划 |
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| 中文摘要: |
| 艾里光束通常是在液晶空间光调制器上加载立方相位后再作傅里叶变换产生，或者在材料表面设计微结构来激发表面等离激元产生。但是前者不利于系统的集成化和小型化，后者通常用于产生一维艾里光束。为了克服这些缺点，利用具有亚波长单元结构的介电质超表面产生艾里光束。将高斯分布的振幅信息和立方相位信息同时编码来对平面波进行调制，并对比了振幅和相位同时调制以及仅相位调制的差异，同时利用有限时域差分（FDTD）算法进行了仿真。研究表明：在工作波长为630 nm时可以产生准艾里光束，并发现这种利用傅里叶变换来产生艾里光束的方法，其傅里叶频谱的振幅信息是可以忽略的，由此简化了超表面编码流程；所设计的超表面的偏振转化效率高达83%，器件直径仅为35 μm，厚度仅为380 nm，可为光学系统的集成化提供参考。 |
| 英文摘要: |
| Airy beams are usually generated by Fourier transform after loading a cubic phase on the liquid crystal spatial light modulator or generation of Airy form surface plasmons based on microstructures on the surface of the material. Nevertheless, the limitations of the spatial light modulator hinder the integration and miniaturization of the device. The latter is usually used to generate one-dimensional Airy beams. Concerning to overcome these shortcomings, a dielectric metasurface with a sub-wavelength unit cell is utilized to substitute the function of the traditional spatial light modulator. The finite difference time domain (FDTD) method is employed to generate the quasi Airy beam at the wavelength of λ = 630 nm. The attained polarization conversion efficiency is as high as 83%. The diameter of the designed metasurface device is only 35 μm while the thickness is only 380 nm, which provide a reference for the integration and miniaturization of the optical systems and devices. |
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