摘要
原子时间成像开辟了微观(分子/原子)动力学研究的新时代。在原子水平上,物理学、化学和生物学的研究是统一的,都是研究原子的运动和原子态的变化。原子时间成像只能是全光成像,利用光的两重性(既是信息载体,又是研究资源)记录瞬变动态过程(事件)调制的光场信息。本文对原子时间成像的基本原理、最佳成像系统及其成像的典型技术进行评述。目前已利用多级光参量放大闲频光(直接)成像技术,记录了有效成像频率为40×10^(12) frame/s的高空间分辨率等离子体光栅演变过程。
Significance Observing light information during atomic time processes to accurately reveal the physical,chemical,and biological phenomena and their evolution during atomic motion has always been a dream of scientists.Atomic time imaging with the sound intrinsic spatial resolution is applicable to studying ultrafast transient events in ultrafast physics,ultrafast chemistry,and ultrafast biology.The events include ultrafast optophysical processes in semiconductor and quantum well microstructures,excitation of excitons and carriers by light,high-order harmonic effects,ultrafast dynamic processes in condensed matter,ultrahigh-intensity laser wake field acceleration,formation and breaking of chemical bonds,transfer of protons and electrons,the influence of molecular vibrations and rotations on chemical reactions,energy transfer processes in photosynthesis,photoisomerization processes in visual systems,and charge and proton transfer in DNA.Currently,only all-optical imaging can be employed to achieve atomic time imaging,where light itself records the modulated light field of transient events or dynamic processes.This is based on the duality of light as both an information carrier and a research resource.From the perspective of the light field,the amplitude,phase,wavelength,wave vector,and polarization of the light field are included.From the perspective of photons,photon energy,momentum,spin angular momentum,orbital angular momentum,and nonlinear and quantum properties of photons are contained.Progress Ultrafast atomic time imaging has seen significant developments in recent years.In femtosecond holographic imaging,Dr.Martin Centurion was the first to achieve multi-frame encoded femtosecond time-domain holography(Fig.5),while Dr.N.H.Matlisi first utilized chirped pulses and spectral interferometry to record the frequency-domain holography of laser-induced plasma wake fields(Fig.6).In scanning streak tube compressed ultrafast photography(CUP),Gao et al.proposed the CUP technique to achieve two-dimensional imaging of non-repetitive ultrafast luminescent phenomena(Fig.8).This caused a sensation in the ultrafast imaging field,which opened up a new avenue for atomic time imaging via adopting compressed sensing algorithms,thus leading to the emergence of T-CUP,CUSP,and other related derivative technologies.In spectrum-plane encoded atomic time imaging,Ehn et al.proposed the frequency recognition algorithm for multiple exposures(FRAME),which enabled ultrafast multi-frame imaging with high spatial and temporal resolution(Fig.9).Zhu et al.proposed the frequency domain integration sequential imaging(FISI)technique,achieving the highest space-bandwidth product in ultrafast imaging to date(Fig.10).In spectral encoding femtosecond imaging,Nakagawa et al.proposed the sequential timed all-optical mapping photography(STAMP),with a maximum framing frequency of 4.4×1012 frame/s,which was once considered the fastest photography in the world(Fig.11),and this led to the development of technologies such as SF-STAMP(Fig.12).The grating-sampling atomic time imaging technique(OPR)combines the grating sampling theory with spectral-time encoding technology by a grating plate,achieving all-optical high spatial and temporal resolution imaging with a grid principle of 2 trillion frames per second(Fig.13).Multi-stage non-collinear optical parametric amplification(MOPA)idler imaging has parameters such as framing time,exposure time,spatial resolution,and frame size that are independent and unrelated,thus becoming an ideal imaging method.It yields sound effective framing frequency and high spatial resolution in single-shot atomic time-scale imaging(Fig.14).Conclusions and Prospects Further development of the information theory of atomic time imaging is needed to evaluate and develop atomic imaging technology.We preliminarily improve Schardin’s space-time information theory,explore the optimal atomic time imaging system that is not limited by the Heisenberg uncertainty principle,and always pursue shorter exposure time,finer intrinsic spatial resolution,and greater spatial bandwidth products.Atomic time imaging faces new challenges,including advancing studies on high-speed imaging and computational femtosecond imaging information theory,promoting the combination of femtosecond imaging and picometer spatial resolution technology,and exploring new principles of femtosecond imaging,new optimal imaging systems,and reliable,reasonable enhancement of existing imaging technology performance.Additionally,it is necessary to promote the application of atomic time imaging technology in photon materials,plasma physics,live cells,and neural activity,and to push the timescale from femtoseconds to attoseconds.The development of attosecond imaging already shows its initial signs.Currently,the imaging of the electron wave packet motion in neon atoms and electron motion capturing in nitrogen molecules have been achieved,and the temporal resolution of transmission electron microscopy has been pushed to the attosecond scale.By directly measuring the relationship between the electromagnetic functions of natural and artificial materials with space and time,attosecond electron microscopy provides indispensable information for a deep understanding of the fundamental mechanisms of light-matter interactions,and is expected to promote development in fields such as near-field optics,passive and active deformable materials,photonic integrated circuits,photoperiodic photochemistry,and free-electron cavity optics.
作者
李景镇
蔡懿
曾选科
陆小微
陈红艺
徐世祥
朱启凡
朱永乐
Li Jingzhen;Cai Yi;Zeng Xuanke;Lu Xiaowei;Chen Hongyi;Xu Shixiang;Zhu Qifan;Zhu Yongle(College of Physics and Optoelectronic Engineering,Institute of Photonic Engineering,Shenzhen Key Laboratory of Micro-Nano Photonic Information Technology,Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province,State Key Laboratory of Radio Frequency Heterogeneous Integration,Shenzhen University,Shenzhen 518060,Guangdong,China)
出处
《光学学报》
EI
CAS
CSCD
北大核心
2024年第17期73-89,共17页
Acta Optica Sinica
基金
国家自然科学基金国家重大科研仪器研制项目(61827815)
国家自然科学基金(92050203,62275163,12174264,62075138)
国家重点研发计划(2023YFA1608504)
广东省自然科学基金(2021A1515011909,2022A1515011457,2024A1515010437,2024A1515011948)
深圳市科技计划项目(JCYJ20210324095213037)。
关键词
极高速成像
原子时间成像
分幅频率
分幅时间
曝光时间
时间分辨率
本征空间分辨率
时间信息质量因子
空间信息混淆比
ultrafast imaging
atomic time imaging
framing frequency
framing time
exposure time
temporal resolution
intrinsic spatial resolution
time information quality factor
spatial information confusion ratio
作者简介
通信作者:李景镇,lijz@szu.edu.cn。
