平面波透射聚焦超表面结构设计

为实现单个平面透镜在10.6!m波长处的会聚功能,本文设计并制备了一种一维亚波长光栅面型超表面(electromagnetic meta-surface)。基于电磁谐振现象,利用双条形介质耦合结构模型设计了会聚超表面单元结构,并采用FDTD Solution软件进行仿真计算证明了其对光波位相的调制作用,筛选出了10个位相梯度。通过对10个位相梯度的自由组合形成会聚超表面平面透镜,并进行了实验验证。实验结果表明:在设计波长上,超表面平面透镜对TM模式平面波能够较好地实现透射会聚的功能,焦距为49mm,会聚光斑最小宽度是0.7mm,工作效率达到60%。

Plane Wave Transmission Focusing Meta-Surface Structure Design

In order to realise the function of focusing by single flat lens,this paper proposed a electromagnetic focus meta-surface working on 10.6 SymbolmA@_m wavelength which has one dimensional subwavelength grating structure.According to the resonance between dielectric nanostrcture and light,based on the coupled rectangular dielectirc resonators model,unit structure was designed.Using FDTD solution software for simulation,the function of phase modulation can be proved and 10 phase gradient structures can be selected.The meta-surface was designed by the free combination of the 10 structures and tested by experiment.Result shows that,at 10.6 SymbolmA@_m wavelength,when TM mode light incident the meta-surface,transmitted light will be focused,focal length is 49 mm,the minimum value of the spot width is 0.7 mm,and working efficiency can be reached to 60%.