![]() Thus, the concern is with finding not only the fluence that caused a pit (for example) but also the fluence at which that pit begins to grow with subsequent laser shots. Tests were performed to find the functional damage threshold: the minimum fluence at which a damaged optic degrades the performance of the NIF laser, or, experimentally, the minimum more » fluence at which a damaged site begins to grow. The coatings tested were primarily high reflectors, although polarizing beam splitter and antireflective thin films were tested on the small substrates. For both studies, the optics were raster scanned by Q-switched Nd:YAG lasers emitting 1064-nm light with 10-ns pulse lengths. Studies into the functional damage thresholds of hafnia/silica thin-film coatings for the NIF laser have been conducted on two different-sized substrates: 50-mm-diam test substrates and full-sized (412 x 412-mm) NIF mirror substrates. In addition, we show that the differences between hexagonal and square scan geometries are negated when pointing errors and fluence fluctuations from the laser are considered. We also show that multiple passes at low packing densities are temporally equivalent to a single pass with higher packing density, and discuss the advantages of each method. hexagonal), examine the deviations from uniform coverage with each scan geometry and show that hexagonal packing yields lower scan times but is less efficient in coverage than square geometry. We also consider the effect of packing geometry (square vs. Next, more » we develop equations for total scan time for square and round top hat beams and round and rectangular Gaussian beams. We show that 120 Watts of average power is required for a tabletop scanning system at one optic/day. ![]() In this paper we examine raster scanning with small beams from tabletop laser systems. For laser raster scanning to be a viable optical improvement tool for these large optics, damage improvement must be optimized while maintaining scan times of less than 8 hours/optic. = components (lenses, gratings and debris shields) benefits from laser raster scanning using pulsed lasers in the 350 nm range.
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