Chromatic confocal electron microscopy with a finite pinhole size

Abstract

Scanning confocal electron microscopy (SCEM) is a new imaging mode in electron microscopy. Spherical aberration corrected electron microscope instruments fitted with two aberration correctors can be used in this mode which provides improved depth resolution and selectivity compared to optical sectioning in a conventional scanning transmission geometry. In this article, we consider the depth resolution and energy resolution in the confocal optical configuration for SCEM using inelastically scattered electrons with a finite pinhole size. We experimentally demonstrate energy-filtered optical sectioning in a double aberration-corrected instrument with uncorrected chromatic aberration without using a dedicated energy filter.