Statistical description of laser damage initiation in NIF and LMJ Optics at 355 nm

Abstract

Understanding the "extreme statistics" of failure at a weak link allows extrapolation of the results of small area laser damage tests to predict damage levels for the large areas pertinent to NEVLMJ. Conceptually, it is important to focus on the fluence dependence of the surface density of damage sites. Results of different types of damage tests can be reported in terms of this sample characteristic property.

Characterization of 355 nm laser-induced damage of mitigated damage sites in fused silica

“…It is found that both substrates and mitigated sites obey the normal law. The LIDT distribution of the substrate is similar to the results reported by Krol et al [5] and Dijon et al [8]. They pointed out that the normal law or Weibull distribution could be used to describe the character of the threshold distribution of the coating and substrate of optics.…”

“…Damage test results are usually presented using the cumulative damage probability, i.e., S-curve [5,8]. The average R-on-1 LIDT as a function of the cumulative probability of the substrate and mitigated sites is shown in figure 2.…”

“…Except the factors mentioned previously, bubbles, redeposited debris and the morphology of mitigated sites also contribute to the discrepancy in LIDTs of the mitigated sites. Krol et al [5] and Dijon et al [8] utilized a statistical description to analyze the LIDTs of substrate and coating of optics. At present, most studies on mitigated sites focus on how to mitigate the damage sites in an optimal way and decrease the downstream intensification resulting from the mitigated sites [9][10][11].…”

Improved laser induced damage thresholds of Ar ion implanted fused silica at different ion fluences

“…Because of its excellent optical, thermal and mechanical properties, fused silica is one of the important optical materials widely used as transparency optics for high power laser systems [1][2][3]. However, laser induced damage leads to performance degradation of fused silica optics, and seriously reduces the lifetime of the optics and the load capacity of the high power laser facilities.…”

Quantitative measurement of CO2laser-induced residual stress in fused silica optics

“…In particular, it serves as beam-transport lenses and vacuum windows for the large laser facilities such as the National Ignition Facility in the USA, 1 the Laser Megajoule in France, 2 and the SG-III laser facility in China. 3 The lifetime of fused silica components under UV laser irradiation has been extensively investigated and the results show that the lifetime of fused silica optics is determined by both surface damage initiation and damage growth.…”