Tavabi Amir H, Rosi Paolo, Rotunno Enzo, Roncaglia Alberto, Belsito Luca, Frabboni Stefano, Pozzi Giulio, Gazzadi Gian Carlo, Lu Peng-Han, Nijland Robert, Ghosh Moumita, Tiemeijer Peter, Karimi Ebrahim, Dunin-Borkowski Rafal E, Grillo Vincenzo
Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany.
Dipartimento FIM, Universitá di Modena e Reggio Emilia, 41125 Modena, Italy.
Phys Rev Lett. 2021 Mar 5;126(9):094802. doi: 10.1103/PhysRevLett.126.094802.
The component of orbital angular momentum (OAM) in the propagation direction is one of the fundamental quantities of an electron wave function that describes its rotational symmetry and spatial chirality. Here, we demonstrate experimentally an electrostatic sorter that can be used to analyze the OAM states of electron beams in a transmission electron microscope. The device achieves postselection or sorting of OAM states after electron-material interactions, thereby allowing the study of new material properties such as the magnetic states of atoms. The required electron-optical configuration is achieved by using microelectromechanical systems technology and focused ion beam milling to control the electron phase electrostatically with a lateral resolution of 50 nm. An OAM resolution of 1.5ℏ is realized in tests on controlled electron vortex beams, with the perspective of reaching an optimal OAM resolution of 1ℏ in the near future.
传播方向上的轨道角动量（OAM）分量是描述电子波函数旋转对称性和空间手性的基本量之一。在此，我们通过实验展示了一种静电分选器，可用于分析透射电子显微镜中电子束的OAM状态。该装置在电子与材料相互作用后实现对OAM状态的后选择或分选，从而能够研究新材料特性，如原子的磁态。所需的电子光学配置是通过使用微机电系统技术和聚焦离子束铣削来实现的，以50纳米的横向分辨率静电控制电子相位。在对受控电子涡旋束的测试中实现了1.5ħ的OAM分辨率，并且有望在不久的将来达到1ħ的最佳OAM分辨率。
