Fig. 3: Electron optical characterization of µMCPO devices; electron vortex phase plate and dipole.
From: Tailoring electron beams with high-frequency self-assembled magnetic charged particle micro optics
a Protochips Fusion™ TEM specimen holder with an inserted and electrically contacted chip carrying a complete set of self-assembled micro-coils and one micron-sized magnetic pole. The pole, made of a soft magnetic micro-wire, was tapered towards the tip (SEM overview in the bottom inset). The electron beam passes through the aperture in the Si chip (as shown in top inset). b Projected B-field components in x and y direction at different excitation currents Ic, and the corresponding B-field vectors, as determined by differential phase contrast (DPC) measurements. c Phase of the electron wave at 100 mA coil excitation as reconstructed from the DPC measurements. The integration path for computing the vortex orbital angular momentum (OAM) is indicated revealing a strong >104 OAM. d A series of electron (half) vortex beams in the far field (indicated defocus of −0.4 µm) at varying currents, demonstrating the functionality of the adaptive vortex phase plate allowing to modulate the electron beam and OAM on-the-fly. e Schematics inside of a TEM of a dipole; the micro-coils generate a magnetic field transversal to the e− beam; the deflection α can be derived from the camera length L and the displacement d of the center of mass of the beam measured on the detector in the far field. f DPC measurements of the deflection angle of the beam in between the poles of the µMCPO including variations at different sweeps exhibiting a nearly anhysteretic magnetization behavior.
