Spatial control of photoemitted electron beams using a microlens-array transverse-shaping technique

A transversely inhomogeneous laser distribution on the photocathode surface generally produces electron beams with degraded beam quality. In this paper, we explore the use of microlens arrays to dramatically improve the transverse uniformity of an ultraviolet drive-laser pulse used in a photoinjector. We also demonstrate a capability of microlens arrays to generate transversely modulated electron beams and present an application of such a feature to diagnose the properties of a magnetized beam.