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

The modeling of the optical properties of the acceleration field and objective lens of a photoemission electron microscope (PEEM) is presented. Theory to calculate the aberrations of the extraction field was derived, and extended to include relativistic effects. An analysis of the microscope's electron optical performance and aberrations has been performed using an analytical model as well as a ray tracing method. Ray tracing 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 ray tracing and full analytical treatments agree to very high precision. This allows us now to use the ray tracing method in situations where analytical methods are difficult, such as an aberration compensating electron mirror. (C) 2002 American Institute of Physics.