Development of a laser damage growth mitigation process, based on CO₂ laser micro processing, for the Laser MegaJoule fused silica optics

LMJ 2023 facility status

“…In order not to impact the total beam energy for the experiments, this technique is limited to about ten beam blockers per optic at the location of the damage sites. (ii) The Carbon Dioxide (CO2) laser optics mitigation that consists in machining a cone with a CO2 laser to remove the damage site fractures and thus to stop the damage growth [5], [6], [7]. This operation cannot be performed directly on the facility and requires maintenance of the optical component.…”

Application of light diffraction theory to qualify the downstream light field modulation property of mitigated KDP crystals

“…These damage points generally manifest as laser ablation, micro-cracks, micro-pits or other forms, which seriously limit the light propagation characteristics and service life of the KDP crystal [8][9][10]. In order to guarantee the performance of these crystals and prolong their life, the concepts of optics repair and recycling strategy are usually proposed [11,12]. When the laser damage points on the surface of KDP crystal are replaced with a pre-designed smooth contour, the growth of damage on the surface of the crystal is significantly mitigated [13,14].…”