Modeling the acceleration field and objective lens for an aberration corrected photoemission electron microscope

Abstract

The modeling of the optical properties of the acceleration field and objective lens of a photoemission electron microscope is presented. Theory to calculate the aberrations of the extraction field was derived, and extended to include relativistic effects. An analysis of the microscopes electron optical performance and aberrations has been performed using an analytical model as well as a raytracing method. Raytracing has the flexibility needed for the assessment of aberrations where the geometry is too complex for analytical methods. This work shows that in the case of a simple PEEM front end of the acceleration gap and objective lens, the all orders raytracing and full analytical treatments agree to very high precision. This allows us now to use the raytracing method in situations where analytical methods are difficult, such as an aberration compensating electron mirror.

Imaging at the Mesoscale (LEEM, PEEM)

“…For example Möllenstedt et al [32] imaged standing light waves in dielectric layers with varying thickness and Huang [33] used an electrostatic three-electrode immersion lens to image thin samples with electrons excited by X-rays ("X-ray image converter microscopy"). Spivak et al [34] produced the first PEEM images of ferromagnetic domains with a very simple system reducing the work function by a Cs-Sb coating so that visible light could be used for excitation.…”