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高阈值的KTP晶体的研发,对高能激光领域至关重要。采用高重复频率的紫外激光对KTP进行烧蚀,并对烧蚀前后的Raman光谱进行分析,研究发现:激光等离子体效应是造成晶体破坏的主要原因,其逆韧致吸收效应会大大增加激光脉冲能量的沉积,电离效应使得晶体发生充分的离解,高压冲击波效应则把熔化、气化以及电离混合物外排的同时,使得材料发生断裂。烧蚀前后的Raman光谱的特征峰分布基本相同,说明烧蚀作用没有改变KTP材料的整体结构。但是,特征峰的对比值(RIR)都发生了改变,且有所展宽,说明烧蚀后结晶度降低。其中TiO6和PO4等主要氧多面体的特征峰向低波数漂移,说明材料的键合力消弱,更易发生离解。
The development of high-threshold KTP crystals is crucial to the field of high-energy lasers. The KTP was ablated by UV laser with high repetition frequency. The Raman spectra before and after ablation were analyzed. It was found that the laser plasma effect was the main reason for the crystal damage. The reverse absorption effect would increase the laser pulse The deposition of energy, the ionization effect causes the crystal to fully dissociate, and the high-pressure shock wave effect melts, gasifies and ionizes the mixture to drain at the same time, causing the material to fracture. The characteristic peaks of the Raman spectra before and after ablation are basically the same, indicating that ablation does not change the overall structure of the KTP material. However, the contrast ratio (RIR) of the characteristic peaks has been changed and broadened, indicating a decrease in crystallinity after ablation. Among them, the characteristic peaks of the major oxygen polyhedrons, such as TiO 6 and PO 4, drifted to the low wavenumbers, indicating that the bonding force of the material is weakened and the dissociation occurs more easily.