CEMS, RIKEN (The Institute of Physical and Chemical Research), Hatoyama, Saitama, 350-0395, Japan.
Department of Materials Science, Osaka Prefecture University, Sakai, Osaka, 599-8531, Japan.
Sci Rep. 2018 Jan 17;8(1):1008. doi: 10.1038/s41598-018-19380-4.
Advanced electron microscopy technologies have made it possible to perform precise double-slit interference experiments. We used a 1.2-MV field emission electron microscope providing coherent electron waves and a direct detection camera system enabling single-electron detections at a sub-second exposure time. We developed a method to perform the interference experiment by using an asymmetric double-slit fabricated by a focused ion beam instrument and by operating the microscope under a "pre-Fraunhofer" condition, different from the Fraunhofer condition of conventional double-slit experiments. Here, pre-Fraunhofer condition means that each single-slit observation was performed under the Fraunhofer condition, while the double-slit observations were performed under the Fresnel condition. The interference experiments with each single slit and with the asymmetric double slit were carried out under two different electron dose conditions: high-dose for calculation of electron probability distribution and low-dose for each single electron distribution. Finally, we exemplified the distribution of single electrons by color-coding according to the above three types of experiments as a composite image.
先进的电子显微镜技术使得进行精确的双缝干涉实验成为可能。我们使用了一台提供相干电子波的 1.2MV 场发射电子显微镜和一个直接检测相机系统，能够在亚秒曝光时间内进行单电子检测。我们开发了一种方法，通过使用聚焦离子束仪器制造的不对称双狭缝，并在“预夫琅和费”条件下操作显微镜，来进行干涉实验，这种条件与传统双狭缝实验的夫琅和费条件不同。在这里，预夫琅和费条件意味着每个单狭缝观察都是在夫琅和费条件下进行的，而双狭缝观察则是在菲涅耳条件下进行的。在两种不同的电子剂量条件下进行了每个单狭缝和不对称双狭缝的干涉实验：高剂量用于计算电子概率分布，低剂量用于每个单电子分布。最后，我们根据上述三种实验类型，通过颜色编码的方式，对单电子的分布进行了举例说明，并将其作为一个复合图像。
