Mitigation of laser damage on fused silica surfaces with a variable profile CO 2 laser beam

Investigation of stress induced by CO2 laser processing of fused silica optics for laser damage growth mitigation

“…For instance, the influence of irradiation parameters with models taking into account heating, evaporation and stress generation has been studied [5,6]. Some parametric studies have been conducted in order to determine optimum irradiation conditions [7][8][9] and different protocols have been developed to increase the efficiency of the technique [10,11]. Dedicated tools have also been developed to characterize the damages sites and the mitigated area [12][13][14].…”

Mitigation of laser damage growth in fused silica by using a non-evaporative technique

“…9(a) and 9(b), it follows that the resistance damage capability for small-sized mitigated damage sites is higher than those of large-sized sites for small-spot and large-spot testing beams. The damage re-initiation of mitigated sites may be attributed to several factors, such as the weakness located between laser-irradiated and non-irradiated regions, [1] bubbles, [6] and a non-healing crack under the crater.…”

“…Once the defects are damaged under high fluence 3ω laser illumination, the damage will grow exponentially under subsequent laser shots. [1,2] Thus, mitigating damage growth on fused silica is important for extending the usable optical lifetime of fused silica. [3−5] The most effective technique is to utilize a tightly focused 10.6 µm CO 2 laser beam to remove the damaged material by a combination of melting and ablation.…”

Effect of annealing on the laser induced damage of polished and CO2 laser-processed fused silica surfaces

“…Strategies and techniques have been developed to prevent the extend of the damage sites under successive irradiations. [5][6][7][8][9][10][11][12][13][14][15] Local CO 2 laser processing in air atmosphere is the main technique used to mitigate laser damage sites on fused silica optics. It is used in volume production on the National Ignition Facility to "repair" the damage sites and recycle the optics, 16 and should be deployed to operate the LaserMegaJoule.…”