In an electron double-slit experiment, an optically zero propagation distance condition (infocus imaging condition), in which the double-slit position was imaged just on the detector plane (image plane), was realized in a 1.2MV field-emission transmission electron microscope. Interference fringes composed of dot images were controlled by using two electron biprisms. Using a V-shaped double slit, we observed the interference features under the pre-interference condition, interference condition and post-interference condition of electron waves. We conclude that it is possible to observe the interference fringes only when the path information of the individual electrons is not available.

在电子双缝实验中，在 1.2MV 场发射透射电子中实现了光学零传播距离条件（聚焦成像条件），其中双缝位置恰好在检测器平面（像平面）上成像显微镜。通过使用两个电子双棱镜来控制由点图像组成的干涉条纹。利用V型双缝，我们观察了电子波在干涉前、干涉条件和干涉后条件下的干涉特征。我们得出结论，只有当单个电子的路径信息不可用时，才有可能观察到干涉条纹。