Biprism interferences of He+-ions

F. Frémont

Nobuya Machida, Kazuhito Furuya

This article describes elucidations of conditions for electron interference observation, device designs, and numerical simulations for the solid-state biprism. The solid-state biprism is solid-state version of the already realized vacuum biprism, and is also proposed as a test ground for electron interference observation and a new conceptual device. Towards the realization of this device, the designed semiconductor device structures show that interference pattern with a pitch of 86 nm and a visibility of 0.6 can be realized with an electron energy of 20 meV, a transverse energy spread of 0.3 meV, and an operation temperature of 4 K.

H.J. Reyher, Hans Christian Bauer, C. Huber +3 more

Akinori Ohshita, Yasuhiro NUMATA, Yukihiro Mametani +1 more

The intensity distributions of electron interference fringes produced by an electron biprism are usually asymmetric with respect to the central fringe. In order to investigate the effect of the noncircular cross-section of the central electrode of the electron biprism on this asymmetry, the intensity distributions of interference fringes were numerically calculated under the condition of the nonuniform radius of curvature of the central electrode. The calculated results were compared with the experimental ones. It was found that the asymmetry of interference fringes can be caused by the nonuniformity of the radius of curvature of the central electrode. Furthermore it was found that the average visibility of the central and adjacent fringes gives a good approximation to the degree of coherence of electron beam also for the asymmetric interference fringes.

A. A. Villaeys, Karl F. Freed

Amir Hossein Tavabi, Chris Boothroyd, Emrah Yücelen +4 more

The key features of quantum mechanics are vividly illustrated by the Young-Feynman two-slit thought experiment, whose second part discusses the recording of an electron distribution with one of the two slits partially or totally closed by an aperture. Here, we realize the original Feynman proposal in a modern electron microscope equipped with a high brightness gun and two biprisms, with one of the biprisms used as a mask. By exciting the microscope lenses to conjugate the biprism plane with the slit plane, observations are carried out in the Fraunhofer plane with nearly ideal control of the covering of one of the slits. A second, new experiment is also presented, in which interference phenomena due to partial overlap of the slits are observed in the image plane. This condition is obtained by inserting the second biprism between the two slits and the first biprism and by biasing it in order to overlap their images.