基于氧化石墨烯薄膜的菲涅耳透镜设计

Design of Fresnel lens based on graphene oxide film

二维材料具有高折射率和高透光率等优异光学特性,利用激光加工氧化石墨烯材料,会发生还原反应并生成具有类石墨烯材料特性的还原氧化石墨烯,这使得基于氧化石墨烯材料设计菲涅耳透镜成为可能。相较于传统的光学透镜及微型光学透镜,这一设计将透镜的尺寸从厘米级缩减到纳米级。针对工作波长532 nm设计了基于氧化石墨烯薄膜的菲涅耳透镜,通过瑞利–索末菲衍射理论及电磁场数值仿真测试了菲涅耳透镜的聚焦效果,并且通过滴铸法制备了氧化石墨烯薄膜(约500 nm),在薄膜上用激光加工菲涅耳透镜,最终得到透镜聚焦光斑直径2.14µm,聚焦效率41.2%。相比旋涂法制备氧化石墨烯薄膜,滴铸法制备氧化石墨烯具有效率高、价格低廉的优点。该设计为纳米级的基于氧化石墨烯的光学系统的集成化和大规模生产提供了可能。

Two-dimensional materials have excellent optical properties such as high refractive index and high transmittance.At the same time,when graphene oxide materials are processed by laser,reduction reaction occurs and reduced graphene oxide with graphene-like characteristics is generated,which makes it possible to design Fresnel lenses based on graphene oxide materials.Compared with the traditional optical lens and micro optical lens,this design reduces the lens size from centimeter to nanometer level.In this paper,a Fresnel lens based on graphene oxide film is designed for the working wavelength of 532 nm.The focusing effect of the Fresnel lens is tested by Rayleigh-Sommerfeld diffraction theory and numerical simulation of electromagnetic field.The graphene oxide film is prepared by the drop-casting method with the thickness of about 500 nm,and the Fresnel lens is processed by laser on the film.Finally,the diameter of the focus spot is 2.14µm,and the focusing efficiency is 41.2%.Compared with the spraying method for preparing graphene oxide films,the drop-casting method for preparing graphene oxide has the advantages of high efficiency and low cost.This design provides the possibility for the integration and large-scale production of nanometer scale graphene oxide based optical systems.