高损伤阈值Nd:YAG三倍频激光薄膜的研制
文献类型：学位论文
| 作者 | 余华 |
| 学位类别 | 博士 |
| 答辩日期 | 2008 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 邵建达 |
| 关键词 | 薄膜材料 增透膜 高反膜 激光损伤阈值 三倍频 |
| 其他题名 | Preparation of high damage threshold coatings for third harmonic Nd:YAG laser application |
| 中文摘要 | 采用不同的沉积方法和工艺参数制备了紫外波段薄膜材料MgF2、LaF3和Al2O3的单层膜。研究发现MgF2单层膜采用热舟蒸发可以获得比电子束蒸发更高的激光损伤阈值。LaF3单层膜在较高沉积温度和较慢沉积速率下的抗激光损伤能力较强。对电子束制备的Al2O3的单层膜，使用适当的退火温度可以使其抗激光损伤能力略有增强。 进行了不同材料和基底上的三倍频增透膜性能的研究。分别采用电子束蒸发和热舟蒸发，使用膜厚修正挡板制备了膜系结构为Sub|1.5L0.6H1.1L|Air的 Al2O3/MgF2和LaF3/MgF2增透膜。两类增透膜的剩余反射都很低，LaF3/MgF2增透膜具有更强的抗激光损伤能力，其中JGS1基底上的LaF3/MgF2增透膜比UBK7基底上的激光损伤阈值更高。 对45°入射的高反膜的性能进行了初步研究。结果表明氟化物高反膜存在着反射率和激光损伤阈值同时提高的矛盾。针对这个问题，设计制备了组合高反膜，在获得高反射率的同时，抗激光损伤能力也得到了很大的提高。45°S分量组合高反膜随着顶层氟化物膜层数的增加和沉积温度的升高，反射率和激光损伤阈值都得到提高。45°P分量组合高反膜的激光损伤阈值，大大低于氟化物反射膜，而且不同膜层数组合高反膜之间的阈值没有差别，主要是由于组合高反膜的制备方法和P分量下组合高反膜中相对大且特殊的电场分布造成的。尽管如此，与氧化物膜相比，组合高反膜的损伤阈值仍然得到了提高。不同高反膜在P分量下的损伤阈值均远小于其在S分量下的损伤阈值，主要原因也在于此。 以温度场理论为依据，模拟了高反膜和增透膜在不同条件下的温度场分布。模拟结果表明，通过优化工艺，高反膜和增透膜可以达到很高的抗激光损伤能力。 |
| 英文摘要 | MgF2, LaF3 and Al2O3 monolayers were prepared by different deposition methods and technical parameters. The results showed that the MgF2 monolayer deposited by thermal boat evaporation had larger LIDT than that deposited by electron beam evaporation. The higher temperature and slower deposition rate were helpful for improving LIDT of LaF3 layer. LIDTs of Al2O3 monolayers were improved a little at appropriate annealing temperatures. The properties of third harmonic antireflection coatings were studied. Combining masking technology, the electron beam and thermal boat evaporation were employed to prepare Al2O3/MgF2 and LaF3/MgF2 antireflection coatings, respectively, with a design of Sub|1.5L0.6H1.1L|Air. These two kinds of antireflection coatings both had very low reflectance. Moreover, LaF3/MgF2 antireflection coating had higher LIDT. Meanwhile, LaF3/MgF2 antireflector upon JGS1 subtrate had greater laser resistance than that upon UBK7. The pilot study was performed on the properties of reflectors at 45°incidence. The result showed that it was difficult for the fluoride reflector to improve reflectance and LIDT at the same time. The double stack reflector obtained resolved the above problem, the reflectance and LIDT of which were both raised. With the number of layers and the temperature increasing, the reflectance and LIDT of them were improved for S polarization at 45°incidence. The LIDT of the double stack reflector for P polarization at 45°incidence was lower than that of fluoride reflector. Moreover, the LIDTs between reflectors with different number of layers had no distinction. The main reasons were the preparation method which obtained the double stack reflector and the special electric field distribution for P polarization. Whereas, the LIDT of the double stack reflector was still higher than that of the oxide reflector. On the other hand, the LIDTs of three kinds of reflectors for P polarization were much lower than those for S polarization. The reason was the same to the former. Based on the temperature field theory, the temperature rise was simulated for reflectors and antireflectors under different conditions. The results showed that the reflector and antireflector could achieve very high laser resistance. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15246]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 余华. 高损伤阈值Nd:YAG三倍频激光薄膜的研制[D]. 中国科学院上海光学精密机械研究所. 2008. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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