Comparison of material response in fused silica and KDP following exit surface laser- induced breakdown

Abstract

Crater formation that accompanies laser-induced damage is the result of material ejection following the rapid, localized heating to temperatures on the order of 1 eV. The objective of this work is to compare the material ejection behavior in fused silica and KDP crystals as captured using time-resolved shadowgraphy. These two materials are of fundamental importance in ICF class laser systems but they also represent materials with significantly different physical properties. We hypothesize that these different properties can affect the material ejection process.

Dynamic behavior modeling of laser-induced damage initiated by surface defects on KDP crystals under nanosecond laser irradiation

“…This phenomenon is consistent with the liquid ejection behavior experimentally observed in the laser damage processes reported in refs. 37,38 . As the material properties of high-temperature phase transition region are affected by multiple physical parameters such as temperature, pressure, ionization and so on, a small parameter change would incur a huge impact on the morphology of laser damage crater.…”

Recent Advances in Laser-Induced Surface Damage of KH2PO4 Crystal

“…In order to explore the magnitude and effect of stress more concisely, Zeng et al [94] conducted further investigation and found a second wave would be generated inside the fused silica due to the high back-pressure of the laser-generated plasma, as shown in Figure 19b. In addition, Demos et al [95] explored and compared the kinetic behavior of KDP and fused silica under laser irradiation. It is clear that the expansion of shockwaves in air in Figure 19a is quite similar in both materials at the same delay time, which also suggests that the initial energy deposited in a single laser-induced breakdown event was roughly the same.…”

“…It is clear that the expansion of shockwaves in air in Figure19a is quite similar in both materials at the same delay time, which also suggests that the initial energy deposited in a single laser-induced breakdown event was roughly the same. [95]. c1 The distribution of thermal stress due to temperature gradient and expansion; c2 The deformation of crystal materials under tensile stress [87].…”

“…For crystal materials, plastic deformation will occur when the temperature of the irradiated area [95]. c1 The distribution of thermal stress due to temperature gradient and expansion; c2 The deformation of crystal materials under tensile stress [87].…”

“…The shockwave propagating is denoted by an arrow [94]; (b) Propagation of shockwaves in materials. The shock front (S), back-pressure induced shock wave (B); (c) Analysis of the stress action on crystal material under laser irradiation[95]. c1 The distribution of thermal stress due to temperature gradient and expansion; c2 The deformation of crystal materials under tensile stress[87].…”