3D photothermal microscope for the detection of nano-sized absorbing defects responsible for laser-induced damage initiation

2005 ◽  
Author(s):  
Bertrand Bertussi ◽  
Jean Yves Natoli ◽  
Mireille Commandre
Keyword(s):  
Damage Initiation ◽  
Laser Induced Damage

scholarly journals Performance of rapid-grown KDP crystals with continuous filtration

2015 ◽  
Vol 3 ◽  
Author(s):  
Guohang Hu ◽  
Yueliang Wang ◽  
Junxiu Chang ◽  
Xiaoyi Xie ◽  
Yuanan Zhao ◽  
...  
Keyword(s):  
Near Infrared ◽  
Laser Damage ◽  
Damage Resistance ◽  
Damage Initiation ◽  
Micron Size ◽  
Continuous Filtration ◽  
Laser Induced Damage ◽  
Almost All ◽  
Lower Correlation ◽  
Kdp Crystals

Rapid growth processing of KDP crystals was improved by employing continuous filtration to eliminate bulk defects. The performances of the KDP crystals, including scattering defects, laser damage resistance and transmittance, were measured and analyzed. Compared with rapid-grown KDP without continuous filtration, the transmittance in the near-infrared was increased by at least 2%, almost all of ‘micron size’ defects were eliminated and ‘sub-micron size’ defects were decreased by approximately 90%. Laser damage testing revealed that the laser-induced damage thresholds (LIDTs), as well as the consistency of the LIDTs from sample to sample, were improved greatly. Moreover, it identified that ‘micron size’ defects were the precursors which initiated laser damage at relative lower laser fluence (4–6 J cm−2), and there was a lower correlation between smaller size scattering defects and laser damage initiation. The improved consistency in the LIDTs, attributed to elimination of ‘micron size’ defects, and LIDT enhancement originated from the decreased absorption of the KDP crystals.

scholarly journals Laser-Induced Damage Initiation and Growth of Optical Materials

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Jingxia Yu ◽  
Xia Xiang ◽  
Shaobo He ◽  
Xiaodong Yuan ◽  
Wanguo Zheng ◽  
...  
Keyword(s):  
Rear Surface ◽  
Field Enhancement ◽  
Damage Mechanism ◽  
Theoretical Research ◽  
Experimental Investigations ◽  
Integrated Analysis ◽  
Electron Avalanche ◽  
Damage Initiation ◽  
Laser Induced Damage ◽  
Thermal Absorption

The lifetime of optical components is determined by the combination of laser-induced damage initiation probability and damage propagation rate during subsequent laser shots. This paper reviews both theoretical and experimental investigations on laser-induced damage initiation and growth at the surface of optics. The damage mechanism is generally considered as thermal absorption and electron avalanche, which play dominant roles for the different laser pulse durations. The typical damage morphology in the surface of components observed in experiments is also closely related to the damage mechanism. The damage crater in thermal absorption process, which can be estimated by thermal diffusion model, is typical distortion, melting, and ablation debris often with an elevated rim caused by melted material flow and resolidification. However, damage initiated by electron avalanche is often accompanied by generation of plasma, crush, and fracture, which can be explained by thermal explosion model. Damage growth at rear surface of components is extremely severe which can be explained by several models, such as fireball growth, impact crater, brittle fracture, and electric field enhancement. All the physical effects are not independent but mutually coupling. Developing theoretical models of multiphysics coupling are an important trend for future theoretical research. Meanwhile, more attention should be paid to integrated analysis both in theory and experiment.

scholarly journals Recent Advances in Laser-Induced Surface Damage of KH2PO4 Crystal

2020 ◽  
Vol 10 (19) ◽  
pp. 6642 ◽  
Author(s):  
Mingjun Chen ◽  
Wenyu Ding ◽  
Jian Cheng ◽  
Hao Yang ◽  
Qi Liu
Keyword(s):  
Laser Irradiation ◽  
Inertial Confinement Fusion ◽  
Short Pulse ◽  
Damage Threshold ◽  
Damage Mechanism ◽  
Inertial Confinement ◽  
Pulse Laser Irradiation ◽  
Damage Initiation ◽  
Three Stages ◽  
Laser Induced Damage

As a hard and brittle material, KDP crystal is easily damaged by the irradiation of laser in a laser-driven inertial confinement fusion device due to various factors, which will also affect the quality of subsequent incident laser. Thus, the mechanism of laser-induced damage is essentially helpful for increasing the laser-induced damage threshold and the value of optical crystal elements. The intrinsic damage mechanism of crystal materials under laser irradiation of different pulse duration is reviewed in detail. The process from the initiation to finalization of laser-induced damage has been divided into three stages (i.e., energy deposition, damage initiation, and damage forming) to ensure the understanding of laser-induced damage mechanism. It is clear that defects have a great impact on damage under short-pulse laser irradiation. The burst damage accounts for the majority of whole damage morphology, while the melting pit are more likely to appear under high-fluence laser. The three stages of damage are complementary and the multi-physics coupling technology needs to be fully applied to ensure the intuitive prediction of damage thresholds for various initial forms of KDP crystals. The improved laser-induced damage threshold prediction can provide support for improving the resistance of materials to various types of laser-induced damage.

UHV-TEM studies of laser-induced damage

1991 ◽  
Vol 49 ◽  
pp. 632-633
Author(s):  
T.S. Savage ◽  
R. Ai ◽  
D. Dunn ◽  
L.D. Marks
Keyword(s):  
Surface Science ◽  
Rapid Heating ◽  
Local Heating ◽  
Routine Practice ◽  
Transmission Electron ◽  
Northwestern University ◽  
Laser Induced Damage ◽  
Set Up ◽  
Focusing Lens ◽  
Diffusion Of Impurities

The use of lasers for surface annealing, heating and/or damage has become a routine practice in the study of materials. Lasers have been closely looked at as an annealing technique for silicon and other semiconductors. They allow for local heating from a beam which can be focused and tuned to different wavelengths for specific tasks. Pulsed dye lasers allow for short, quick bursts which can allow the sample to be rapidly heated and quenched. This short, rapid heating period may be important for cases where diffusion of impurities or dopants may not be desirable.At Northwestern University, a Candela SLL - 250 pulsed dye laser, with a maximum power of 1 Joule/pulse over 350 - 400 nanoseconds, has been set up in conjunction with a Hitachi UHV-H9000 transmission electron microscope. The laser beam is introduced into the surface science chamber through a series of mirrors, a focusing lens and a six inch quartz window.

Thermally induced damage initiation and growth in carbon-carbon composites

1997 ◽  
Author(s):  
Clinton Chapman ◽  
John Whitcomb ◽  
Clinton Chapman ◽  
John Whitcomb
Keyword(s):  
Carbon Composites ◽  
Thermally Induced ◽  
Damage Initiation
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