基于偏振编码的极高速成像  

Ultrafast Imaging Based on Polarization Encoding

作　　者：朱启凡 蔡懿[1] 曾选科[1] 龙虎 曾亮维 朱永乐 李景镇[1] 陆小微[1] Zhu Qifan;Cai Yi;Zeng Xuanke;Long Hu;Zeng Liangwei;Zhu Yongle;Li Jingzhen;Lu Xiaowei(College of Physics and Optoelectronic Engineering,Shenzhen University,Shenzhen 518060,Guangdong,China)

机构地区：[1]深圳大学物理与光电工程学院,广东深圳518060

出　　处：《光学学报》2022年第20期65-73,共9页Acta Optica Sinica

基　　金：国家自然科学基金重大科研仪器研究项目(61827815);国家自然科学基金(62075138);广东省自然科学基金(2021A1515011909);深圳市基础研究项目(JCYJ20190808164007485,JCYJ202103240-95213037);深圳大学自然科学基金(860-000002110213)。

摘　　要：在现有单次测量极高速成像方法中,直接成像方法的分辨率高但探测系统复杂,而计算成像方法探测系统简单但易损失空间分辨率。因此,提出一种基于偏振编码的极高速成像技术。所提成像系统利用半波片阵列和偏振片阵列对入射飞秒脉冲、出射飞秒脉冲和动态事件进行偏振编码,并通过线性方程组解码极高速动态的时序图像。通过构建光学模型并仿真,精确还原了多幅图像,验证了所提方案的可行性,理论摄影频率在10^(13)frame/s以上,本征空间分辨率可达114 lp/mm。所提成像系统结合了直接成像和计算成像系统的优势:线性方程组精确求解,不会导致光学系统分辨率损失;时序图像叠加使探测结构只需分光不需要对不同时刻的图像进行空间上的分离,简化了探测器的结构。该极高速成像系统的时间分辨率仅受脉冲宽度限制,可以实现飞秒级动态事件的探测,并且随着脉冲宽度的缩短,其时间分辨率可以得到进一步提升。Among the current single-shot ultrafast imaging methods,the direct imaging methods have high resolutions but complex detection systems,while the computational ones have simple detection systems but easily impaired spatial resolutions.Therefore,ultrafast imaging based on polarization encoding is proposed.This imaging system uses a halfwave plate array and a polarizer array to achieve polarization encoding of the incident femtosecond pulses,emergent femtosecond pulses and dynamic events,and it decodes the ultrafast dynamic time-series images by linear simultaneous equations.Then,several images are accurately restored by constructing an optical model and conducting simulations,and the feasibility of the proposed scheme is verified.In theory,its framing rate can reach more than 10^(13)frame/s,and its intrinsic spatial resolution can be as high as 114 lp/mm.The proposed imaging system combines the advantages of direct and computational imaging systems.Specifically,the results of linear simultaneous equations are accurate,which frees the optical system from resolution impairments.Besides,the superposition of time-series images allows the detection structure to split beams alone,thereby saving the effort of dividing the images of different moments spatially and ultimately simplifying the detection structure.The temporal resolution of the proposed ultrafast imaging system is only constrained by pulse width.This system can be used to achieve the detection of femtosecond dynamic events,and its temporal resolution can be further enhanced by narrowing pulse width.

关 键 词：成像系统 偏振编码 极高速成像 线性方程组 时序图像 飞秒脉冲 

分 类 号：O436.3[机械工程—光学工程]