  We present the design and implementation of a side entry laser system
designed for an ultra-high vacuum scanning transmission electron microscope.
This system uses a versatile probe design enclosed in a vacuum envelope such
that parts can be easily aligned, modified, or exchanged without disturbing the
vacuum. The system uses a mirror mounted on the sample holder such that the
sample can be illuminated without being tilted. Notably the mirror can be
removed and replaced with an ablation target and a higher power laser used to
ablate material directly onto the sample. We argue that new capabilities hold
the potential to transform the electron microscope from an analysis tool
towards a more flexible synthesis system, where atomic scale fabrication and
atom-by-atom experiments can be performed.
