低通量激光多脉冲辐照下 KDP 晶体溶胶-凝胶涂层的损伤分析与机理研究。

Damage analysis and mechanism study of sol-gel coating over KDP crystal under multi-pulse of laser irradiation at low flux.

机构信息

Department of Physics, University of Science and Technology Beijing, Beijing, 100083, People's Republic of China.

Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang, 621900, People's Republic of China.

出版信息

Sci Rep. 2023 Mar 1;13(1):3451. doi: 10.1038/s41598-022-25168-4.

DOI:10.1038/s41598-022-25168-4

PMID:36859452

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC9977767/

Abstract

The purpose of this study is to analyze the damage of antireflective (AR) coating over potassium dihydrogen phosphate (KDP) crystal subjected to multi-pulse laser irradiation at low flux under vacuum. Fresh silica AR was characterized as a reference; Atomic Force Microscope (AFM), Scanning Electron Microscopy (SEM), profilometer, and Scanning Near-Field Optical Microscope Photo-induced Force Microscope (SNOM-PiFM) were employed to analyze the characteristics of coatings. The experimental results indicated that the damage of AR coating over the KDP crystal was mainly caused by partial exfoliation, which exposed silica particles beneath the surface. It was found that the accumulated tensile stress led to coating damage with the increase of laser pulse. The initial coating damage was observed to extend and interconnect to form large-area exfoliation. Splitting mechanism of SiO-Si TO was observed at vibration mode peaks of 1064 cm and 1096 cmshowing progressing irradiation damage. Based on this study, it would be helpful to suppress the damage probability of AR coating over KDP crystal applied in high-power laser systems. Moreover, the applicability of SNOM-PiFM method to study the Infrared Radiation (IR) spectra of ultra-thin coatings with transparent substrates was proposed.

摘要

本研究的目的是分析在低通量真空条件下，多脉冲激光辐照对磷酸二氢钾（KDP）晶体上的减反射（AR）涂层的损伤。新鲜的二氧化硅 AR 涂层被作为参考进行了特征分析；采用原子力显微镜（AFM）、扫描电子显微镜（SEM）、轮廓仪和扫描近场光学显微镜光致力显微镜（SNOM-PiFM）对涂层特性进行了分析。实验结果表明，KDP 晶体上 AR 涂层的损伤主要是由部分剥落引起的，这暴露出表面下的二氧化硅颗粒。研究发现，随着激光脉冲数的增加，累积的拉伸应力导致了涂层的损伤。初始的涂层损伤被观察到扩展和相互连接，形成大面积的剥落。在 1064cm 和 1096cm 的振动模式峰值处观察到 SiO-Si TO 的分裂机制，表明存在持续的辐照损伤。基于这项研究，有助于抑制应用于高功率激光系统的 KDP 晶体上 AR 涂层的损伤概率。此外，还提出了 SNOM-PiFM 方法在研究具有透明衬底的超薄涂层的红外（IR）光谱方面的适用性。