Excimer laser marking, profiling and drilling are usually not performed at the focal region of a lens. It is usually more economical to optimize a process at a relatively low energy density and process larger areas at an image plane of a lens system. Internal(within the resonator, i.e. intracavity) methods as well as external methods are used to achieve goal.
H. J. Kahlert,
"Improved Beam Uniformity In Excimer Lasers", Proc. SPIE 0998, Excimer Beam Applications, (16 December 1988); doi: 10.1117/12.960203; https://doi.org/10.1117/12.960203