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 1.75106 Watts/cm2
and with peak intensity or greater 3.5106 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 10010-6 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.
