Physical Biology Center for Ultrafast Science and Technology, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, CA 91125.
Physical Biology Center for Ultrafast Science and Technology, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, CA 91125
Proc Natl Acad Sci U S A. 2014 Jul 22;111(29):10479-84. doi: 10.1073/pnas.1411650111. Epub 2014 Jul 8.
Four-dimensional multiple-cathode ultrafast electron microscopy is developed to enable the capture of multiple images at ultrashort time intervals for a single microscopic dynamic process. The dynamic process is initiated in the specimen by one femtosecond light pulse and probed by multiple packets of electrons generated by one UV laser pulse impinging on multiple, spatially distinct, cathode surfaces. Each packet is distinctly recorded, with timing and detector location controlled by the cathode configuration. In the first demonstration, two packets of electrons on each image frame (of the CCD) probe different times, separated by 19 picoseconds, in the evolution of the diffraction of a gold film following femtosecond heating. Future elaborations of this concept to extend its capabilities and expand the range of applications of 4D ultrafast electron microscopy are discussed. The proof-of-principle demonstration reported here provides a path toward the imaging of irreversible ultrafast phenomena of materials, and opens the door to studies involving the single-frame capture of ultrafast dynamics using single-pump/multiple-probe, embedded stroboscopic imaging.
四维度多阴极超高速电子显微镜的开发使得对单个微观动态过程在极短的时间间隔内进行多次成像成为可能。该动态过程由单个飞秒光脉冲在样品中引发，并通过单个紫外激光脉冲撞击多个空间上不同的阴极表面产生的多个电子包进行探测。每个电子包都被明显地记录下来，其时间和探测器位置由阴极结构控制。在第一个演示中，每个 CCD 图像帧上的两个电子包以 19 皮秒的间隔探测不同的时间，在飞秒加热后金膜的衍射演化过程中。讨论了进一步阐述这一概念以扩展其功能并扩展 4D 超高速电子显微镜应用范围的未来方案。这里报道的原理验证演示为成像不可逆超快材料现象提供了一条途径，并为使用单泵/多探针、嵌入式频闪成像进行超快动力学的单帧捕获研究开辟了道路。
