基于光场层析的激光超光速运动三维成像  

Snapshot Three-Dimensional Imaging of Superluminal Motion of Pulsed Lasers with Light Field Tomography

作　　者：潘龙 封晓华 Pan Long;Feng Xiaohua(Research Center for Humanoid Sensing,Zhejiang Lab,Hangzhou 311121,Zhejiang,China)

机构地区：[1]类人感知研究中心,之江实验室,浙江杭州311121

出　　处：《中国激光》2023年第11期195-201,共7页Chinese Journal of Lasers

基　　金：国家自然科学基金(62205302);之江实验室科研启动项目(113010-PI2107)。

摘　　要：实时表征超快激光的时域特性是一项非常重要且很有挑战性的工作。现有方法通常仅限于在少数空间点或者二维空间内观测超快激光的传播过程,无法完整记录超快激光在介质中的传播过程,尤其是涉及超光速运动时。作为一种新方法,光场层析技术通过结合智能算法和新型的光学设计,能够以皮秒级时间分辨率对超快现象进行三维成像。笔者借助该技术捕获了超快激光在三维空间中的超光速运动,并证明了在测量超快激光的时空特性时完整考虑激光三维传播过程的重要性。Objective Real-time characterization of temporal behaviors of ultrafast lasers is an important and challenging task.Existing methods are typically limited to a few spatial modes or a two-dimensional(2D)space,which is insufficient for adequately portraying the propagation of ultrafast lasers in a medium when superluminal motion is involved.To accurately characterize the propagation of ultrafast lasers in the presence of superluminal motion,it is necessary to record the complete four-dimensional(4D)space-time(x,y,z,t)in which the laser pulse exists.However,most ultrafast cameras are incapable of three-dimensional(3D)imaging.Additionally,when 2D imaging is performed,the tradeoff between the light throughput and imaging depth of field can be a hindrance for capturing superluminal motions,which typically occurs when the light is propagating at a large angle with respect to the camera plane.The objectives of this study were to develop efficient 3D ultrafast imaging methods that can capture the complete 4D space-time with an extended depth of field and to record and analyze superluminal motions with a high spatiotemporal resolution.Methods Light field tomography(LIFT),which leverages intelligent algorithms and novel optics,is a new method capable of 3D imaging of ultrafast phenomena with a picosecond-scale temporal resolution.The core idea of LIFT is to reformulate image formation as a computed-tomography problem.In LIFT,the spherical lens is replaced with a cylindrical lens,allowing each pixel to record a line integral of the scene along the direction of the invariant axis of the lens(one without optical power).With a one-dimensional(1D)sensor placed at the focal plane of the cylindrical lens,a parallel beam projection of the scene can be obtained,similar to that in X-ray computed tomography.By using a linear array of such cylindrical lenses,each oriented at a distinct angle with respect to the 1D sensor,projection data along different angles can be simultaneously recorded for computationally reconstructing the scene.M

关 键 词：超快光学 超快激光 三维成像 超光速运动 光场成像 

分 类 号：O436[机械工程—光学工程]