Phase-Resolved Electron Guiding in Optimized Chip-Based Microwave Potentials

Abstract

Surface-electrode chips are a versatile and well-established tool for trapping and guiding charged particles. The technique, usually applied to ions, has recently been adapted for electrons using a twodimensional quadrupole guide at microwave driving frequencies. During injection into the guiding potential, the electron trajectories show a strong dependence on the phase and amplitude of fringing electric fields at the coupling entrance of the guide. Here we study the corresponding electron dynamics using a pulsed electron source with pulse durations of several 100 ps to temporally resolve fringing electric fields oscillating at the microwave drive frequency. By synchronizing the timing of the electron pulses to a certain microwave phase, we can increase the electron guiding efficiency by 50%. Furthermore, we present numerically optimized electrode structures for which the amplitude of fringing electric fields at the coupling entrance of the guide is drastically reduced. Particle-tracing simulations suggest that the optimized electrode layout allows the direct injection of electrons into the lowest-lying motional quantum states of the transverse guiding potential.

Designs for a quantum electron microscope

“…This capability allows the fabrication of 2-d traps for electrons based on the generation of the necessary microwave fields by means of properly shaped electrodes on a planar substrate. 48,49 The generation of microwave fields by means of a planar microwave chip provides ease of scalability and the flexibility to engineer versatile guiding potentials in the near-field of the microwave excitation. This feature makes surface-electrode structures ideally suited for the implementation of a double-well potential as originally proposed by Putnam and Yanik.…”

A compact electron matter wave interferometer for sensor technology

“…They are applied to measure the rotational phase shift due to the Sagnac effect [5], to study Coulomb-induced quantum decoherence [6,7], the magnetic Aharonov-Bohm effect [8][9][10][11] or the Talbot-Lau effect for magnetic field sensing [12]. The topic is influenced by recent technical innovations and improvements concerning the beam source [13][14][15], the precise electron guiding [3,16], the coherent beam path separation [4,14,17,18] and the development of spatial and temporal single-particle detection methods [19][20][21][22]. The progress has potential novel applications in electron microscopy [23,24] and sensor technology for inertial forces [25], mechanical vibrations [21] and electromagnetic frequencies [19,20].…”

Second-order correlations in single-particle interferometry

“…In neutron interferometers [16], the quantum-mechanical phase shift due to the Earth's gravitational field was observed [17]. Moreover, remarkable progress was achieved in the field of matter-wave interferometry with charged particles such as electrons and ions [18][19][20] based on new developments concerning the beam source [21][22][23], the precise electron guiding [24,25], the coherent beam path separation by nanostructures [22,[26][27][28] and highly resolved spatial and temporal single-particle detection [29]. This advance opened the door for experiments in Aharonov-Bohm physics [30][31][32] and Coulomb-induced decoherence [13,33,34].…”