Structure, impurity composition, and laser damage threshold of the subsurface layers in KDP and KD*P single crystals
Structure, impurity composition, and laser damage threshold of the subsurface layers in KDP and KD*P single crystals
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DOI：
10.1117/12.240416
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发表时间：
1996-05
期刊：
影响因子：
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通讯作者：
V. I. Salo;L. V. Atroschenko;S. V. Garnov;N. V. Khodeyeva
中科院分区：
文献类型：
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作者：
V. I. Salo;L. V. Atroschenko;S. V. Garnov;N. V. Khodeyeva
本文研究了KDP和KD*P单晶在研磨机械处理过程中出现的亚表层的结构和缺陷程度对其表面激光损伤阈值的影响。结果表明，浮雕多晶层的平坦化，杂质（Ca、Al、Mg、C等）的减少，用于单晶机械处理的磨料和辅助材料引入的浓度以及降低位错浓度导致所研究的晶体对激光辐射损伤的表面电阻显著上升。然而，在最精细的抛光中，表面激光损伤抗性的值相对于体材料的相应值不高于40%。研究了激光辐照下晶体表面损伤中心的典型图形与损伤层的结构和深度的关系。结果发现，在激光辐射的作用下，强烈受损的表面的降解伴随着燃烧或熔化的材料区域的出现，没有形成晶体取向的裂纹。随着次表层断层程度的降低，激光损伤中心表面的典型图案（具有明显明显的裂纹晶体取向）在其看来接近体损伤。
The effect of the structure and degree of faultness of the subsurface layer which appears during the abrasive mechanical treatment of KDP and KD*P single crystals on the value of their surface laser damage threshold was studied in this paper. It was shown that flattening of the relief polycrystalline layer, decrease of the impurity (Ca, Al, Mg, c, etc.) concentration introduced by the abrasive and supplementary materials, used for the mechanical treatment of single crystals, as well as lowering the concentration of dislocations lead to a significant rise of the surface resistance of the studied crystals to the laser radiation damage. However, at a most fine polishing the value of the surface laser damage resistance was not higher than 40% with respect to the corresponding value of the bulk material. Considered were typical patterns of the damage center on the surface of crystals exposed to the laser radiation in connection with the structure and depth of the damaged layer. It was found that the degradation of a strongly damaged surface under the effect of laser radiation is accompanied by the emergence of the burned or melted material areas with no crystallographically oriented cracks formed. The typical pattern the surface of the laser damage center with a clearly pronounced crystallographic orientation of cracks approaches in its view the bulk damage as the degree of faultness of the subsurface layer decreases.