Development of state-of-the-art high-power laser systems requires accurate information about the damage resistance of critical optical components. Since damage threshold fluence decreases significantly with decreasing pulse length, highpower systems based on chirped-pulse amplification are usually limited by the damage threshold of the components utilized for the final pulse compression and transport of the compressed beams. Sub-picosecond laser damage is a complex process involving various nonlinear photoionization and relaxation mechanisms, and no current theory can reliably predict damage threshold values for arbitrary combinations of laser parameters, optical coating properties, and ambient conditions. To evaluate the damage resistance of candidate high-reflectivity coatings for the distribution of compressed PW and multi-PW pulses within experimental areas of the ELI beamlines facility, a series of laser damage tests in high vacuum were conducted. In this work, we present threshold values for high-reflectance (HR) dielectric coatings tested according to different protocols in conditions specific to their operation. We compare results acquired using S-on-1, R-on-1, and Raster Scan routines for several samples and discuss their accuracy.
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