The present invention provides long life
optics for a modular, high repetition rate,
ultraviolet gas
discharge laser systems producing a high repetition rate
high power output beam. The invention includes solutions to a surface damage problem discovered by Applicants on CaF2
optics located in high
pulse intensity sections of the output beam of prototype
laser systems. Embodiments include an enclosed and purged beam path with beam pointing control for
beam delivery of billions of output
laser pulses. Optical components and modules described herein are capable of controlling
ultraviolet laser output pulses with
wavelength less than 200 nm with average output pulse intensities greater than 1.75×106 Watts / cm2 and with
peak intensity or greater 3.5×106 Watts / cm2 for many billions of pulses as compared to prior art components and modules which failed after only a few minutes in these pulse intensities. Techniques and components are disclosed for minimizing the potential for optical damage and for reducing the
pulse energy density to less than 100×10−6 J / cm3. Important improvements described in this specification have been grouped into the following
subject matter categories: (1) Solution to CaF2 surface damage discovered by Applicants, (2) description of a high power ArF MOPA laser
system, (3) description of
beam delivery units, (4) polarization considerations (5) a high speed water-cooled auto
shutter energy
detector module and (6) other improvements.