Within the framework of the laser integration line (LIL) and the laser megajoule, we describe the design, optical characterization, mounting, alignment, and operation on the LIL of large 420 mm x 470 mm transmission gratings. Two types of grating were manufactured. The first, operating at a wavelength of 1.053 microm, was used for deviation purposes. The second, operating at a wavelength of 0.351 microm, was used for both deviation and focusing purposes. We demonstrate that these large transmission gratings are suitable for nanosecond-regime operation on high-power laser facilities.

International audienc

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In this paper, we present various laser conditioning experiments which have been performed with KDP SHG and DKDP THG samples. The different conditioning facilities used delivered laser pulses at 351 nm in the nanosecond (from 3 to 12 ns) or in the sub-ns (600 ps) regime. Finally, the efficiency of the various conditioning protocols was compared: 526 nm-6 ns and 351 nm-3 ns damage tests were performed respectively on SHG and THG samples. The results show that laserconditioning SHG KDP samples at 351 nm either with ns or sub-ns pulses allows reducing the laser damage density so that it becomes consistent with the specification of high power lasers. They also confirm that conditioning THG DKDP samples at 351 nm using sub-ns pulses is more efficient than using ns pulses.