角度复用的光学加密超表面的超快激光嵌套加工方法研究  

Angle-multiplexed optically encrypted metasurfaces fabricated by ultrafast laser induced spatially selective-modified nanograting structures

作　　者：张晓斌 韩伟娜 ZHANG Xiao-bin;HAN Wei-na(Beijing Institute of Technology Chongqing Innovation Center,Chongqing 401120,China;Laser Micro/Nano Fabrication Laboratory,School of Mechanical Engineering,Beijing Institute of Technology,Beijing 100081,China)

机构地区：[1]北京理工大学重庆创新中心,重庆401120 [2]北京理工大学机械与车辆学院激光微纳制造研究所,北京100081

出　　处：《中国光学（中英文）》2023年第4期889-903,共15页Chinese Optics

基　　金：国家重大研发计划(No.2022YFB4602900);重庆市自然科学基金(No.cstc2021jcyj-cxttX0003,No.CSTB2022NSCQ-MSX1322);国家自然科学基金(No.52005041,No.52235009)。

摘　　要：图案信息的光学加密在防伪、信息加密存储等方面具有广泛的应用,基于各向异性功能复用的结构色超表面得到发展。基于一维光栅衍射的光学加密超表面由于需要逐个加工掩模或单元结构,从而导致效率低下;传统激光烧蚀波纹结构(LIPSS)效率高,但所形成的结构均匀、一致性差。基于以上难题,提出了一种基于皮秒激光直写相变材料Ge_(2)Sb_(2)Te_(5)得到的改性结构加工光学超表面的方法。首先,表征所制备的GST改性光栅的色散性能,结合改性光栅的偏振依赖性,设计了角度复用的信息加密超表面。实现了在自然光条件下加密,在强光条件下能够选择性解密读取并动态展示的性能。相比于传统加工方法,本方法可在一次直写过程中以同时打印的形式生成一系列光栅结构,提高了加工效率;同时加工得到的光栅结构均匀一致性好,提高了显色效果。利用取向角相差16°的改性光栅实现了无串扰的选择性信息读取,所得结构色均匀鲜艳。本文提出的加工策略在防伪、信息加密存储及可穿戴柔性显示设备等领域有深刻的应用前景。The optical encrypted metasurface based on one-dimensional grating diffraction requires the processing of mask or unit structure one by one,resulting in low efficiency.In addition,the poor uniformity of the structure formed by conventional ablated LIPSS can also affect device performance.Aming at the above problems,an optical metasurfaces processing method is proposed based on modified structures obtained by picosecond laser direct writing phase-change material Ge_(2)Sb_(2)Te_(5).Firstly,the dispersion properties of the prepared GST-modified gratings are first characterized,and the angle-multiplexed information encryption metasurfaces are designed by combining the polarization dependence of the modified grating,and the metasurface prepared by the proposed method is further demonstrated.In addition,the performance of encryption under natural light conditions and selective decryption reading and dynamic display under strong light conditions has been achieved.Compared to the conventional processing method,the proposed method can generate a series of grating structures in the form of simultaneous printing in a direct writing process,which improves the processing efficiency.At the same time,the grating structure obtained by processing has good uniformity and consistency,which improves the color rendering effect.A modified grating with an orientation angle difference of 16°is used to realize selective information reading without crosstalk resulting in uniform and bright structural colors.The processing strategy proposed in this paper has a profound application prospect in the fields of anti-counterfeiting,information encryption storage and wearable flexible display devices.

关 键 词：超快激光 相变材料 信息加密 光栅结构 

分 类 号：TP394.1[自动化与计算机技术—计算机应用技术] TH691.9[自动化与计算机技术—计算机科学与技术]