We present kilohertz-scale video capture rates in a transmission electron microscope, using a camera normally limited to hertz-scale acquisition. An electrostatic deflector rasters a discrete array of images over a large camera, decoupling the acquisition time per subframe from the camera readout time. Total-variation regularization allows features in overlapping subframes to be correctly placed in each frame. Moreover, the system can be operated in a compressive-sensing video mode, whereby the deflections are performed in a known pseudorandom sequence. Compressive sensing in effect performs data compression before the readout, such that the video resulting from the reconstruction can have substantially more total pixels than that were read from the camera. This allows, for example, 100 frames of video to be encoded and reconstructed using only 15 captured subframes in a single camera exposure. We demonstrate experimental tests including laser-driven melting/dewetting, sintering, and grain coarsening of nanostructured gold, with reconstructed video rates up to 10 kHz. The results exemplify the power of the technique by showing that it can be used to study the fundamentally different temporal behavior for the three different physical processes. Both sintering and coarsening exhibited self-limiting behavior, whereby the process essentially stopped even while the heating laser continued to strike the material. We attribute this to changes in laser absorption and to processes inherent to thin-film coarsening. In contrast, the dewetting proceeded at a relatively uniform rate after an initial incubation time consistent with the establishment of a steady-state temperature profile.

中文翻译：

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透射电子显微镜中的静电子帧和压缩传感视频。

我们使用通常仅限于赫兹级采集的相机在透射电子显微镜中展示千赫兹级视频捕获率。静电偏转器在大型相机上光栅化离散图像阵列，将每个子帧的采集时间与相机读出时间解耦。全变分正则化允许将重叠子帧中的特征正确地放置在每个帧中。此外，该系统可以在压缩感测视频模式下操作，由此以已知的伪随机序列执行偏转。压缩传感实际上在读出之前执行数据压缩，使得重建产生的视频可以具有比从相机读取的像素更多的总像素。例如，这允许在单次相机曝光中仅使用 15 个捕获的子帧来编码和重建 100 帧视频。我们演示了实验测试，包括激光驱动的熔化/去湿、烧结和纳米结构金的晶粒粗化，重建视频速率高达 10 kHz。结果表明该技术可用于研究三种不同物理过程的根本不同的时间行为，从而证明了该技术的强大功能。烧结和粗化都表现出自限行为，即使加热激光继续照射材料，该过程也基本上停止。我们将此归因于激光吸收的变化和薄膜粗化固有的过程。相反，在与稳态温度曲线的建立一致的初始孵育时间之后，去湿以相对均匀的速率进行。