A nanofabricated, monolithic, path-separated electron interferometer

TL;DR

This paper presents a novel, monolithic silicon-based electron interferometer capable of beam path separation and interference measurement within a transmission electron microscope, with potential applications in holography and fundamental physics.

Contribution

The authors fabricated a self-aligned, monolithic electron interferometer from a single silicon crystal, demonstrating beam separation and interference fringes in a standard electron microscope.

Findings

Successfully demonstrated beam path separation.

Observed interference fringes with 0.32 nm period.

Achieved 15% contrast in interference fringes.

Abstract

We report a self-aligned, monolithic electron interferometer, consisting of two 45 nm thick silicon layers separated by 20 $\mu$m. This interferometer was fabricated from a single crystal silicon cantilever on a transmission electron microscope grid by gallium focused ion-beam milling. Using this interferometer, we demonstrate beam path-separation, and obtain interference fringes in a Mach-Zehnder geometry, in an unmodified 200 kV transmission electron microscope. The fringes have a period of 0.32 nm, which corresponds to the $\left[\bar{1}\bar{1}1\right]$ lattice planes of silicon, and a maximum contrast of 15 %. This design can potentially be scaled to millimeter-scale, and used in electron holography. It can also be applied to perform fundamental physics experiments, such as interaction-free measurement with electrons.