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题名	钕玻璃环抛加工工艺研究
作者	曹俊
学位类别	硕士
答辩日期	2015
授予单位	中国科学院上海光学精密机械研究所
导师	魏朝阳
关键词	环抛 钕玻璃 划痕 去除率 中频误差
其他题名	Research of Nd-doped Glass Continuous Polishing Processing Technics
中文摘要	大口径磷酸盐激光钕玻璃作为高功率固体激光驱动装置中的增益介质，它的表面加工质量直接影响到激光系统的性能。随着激光系统输出功率的不断提高，疵病指标的进一步提高，对钕玻璃表面加工的要求也越来越高。目前，大口径磷酸盐钕玻璃的表面加工方法主要就是环形抛光。Zygo公司已经能够加工出全频段达到指标要求的大口径钕玻璃，而国内在这方面的研究还有所欠缺，国内大口径钕玻璃环抛加工存在效率低、面形和表面疵病不易控制等问题，其根本原因是对环形抛光的规律认识不够全面。因此，本论文围绕钕玻璃加工全频段误差控制、抛光机理、表面疵病的控制，开展了在抛光液中添加不同试剂、引入杂质颗粒物、改变开槽方式等方面的工作，主要如下： 将石英玻璃、K9玻璃和钕玻璃放入三孔的分离器中同时抛光，使用不同粒径的抛光粉，滴加适量的草酸和三聚磷酸钠来调节抛光液的pH值，对三种材质玻璃在不同抛光液下的去除率和高频微观结构进行研究分析。实验发现：钕玻璃表面产生疵病的情况是最严重的，玻璃表面产生划痕的数密度随着抛光粉粒径的增大而增加；磷酸盐玻璃的材料去除率高于硅酸盐玻璃；三块玻璃在碱性抛光环境下材料去除速率增大；粒径较小的抛光粉和中性的抛光条件能够加工出表面较好的钕玻璃；K9玻璃不适宜在碱性条件下抛光；石英玻璃可以实现超光滑加工。 通过实验发现不同槽形会引起光学元件表面不同程度的中频误差，槽间距越小越有利于降低中频误差；方形槽抛光钕玻璃得到较小的rms值。基于Preston公式建立抛光的理论模型分析了实验结果，模拟结果表明：圆形槽在抛光玻璃表面留下的环带结构经过中频滤波后会产生中频残差；从模拟的PSD曲线图中可以看出，方形槽抛光玻璃更易于抑制中频误差，得到较小的rms值。 研究了不同杂质颗粒物对划痕的影响及其大小与划痕形貌之间的关系，在钕玻璃抛光过程中分别引入三种尺寸的金刚砂、氧化铈团聚物和用过的抛光粉作为杂质颗粒物，对抛光过程中产生的划痕形貌进行统计分析；实验结果表明：脆性划痕、塑性划痕和混合型划痕都存在，其中脆性划痕占很大比例，氧化铈团聚物和用过的抛光粉产生的划痕浅且少，金刚砂产生的划痕深且多，随着金刚砂粒径的增大，对应产生的划痕的数密度和长度也增加，不同的金刚砂产生的划痕的宽度分布与其对应的粒径分布相似，呈高斯状分布；划痕的宽度与长度都随着引入杂质颗粒物粒径的增大而增加。
英文摘要	Large aperture Nd-doped glass has been used as amplifier in high-peak power lasers. Its surface polishing quality affects that of laser system. The increase of the laser energy output and improvement of surface scratch evaluation index require high surface processing quality of optics. At present, the main surface processing method of large aperture Nd-doped glass is annular polishing. Zygo company has processed Nd-doped glass that meet the standars in full frequency band. But there are still some lacks in domestic research which are low efficiency, hard controlling of surface shape and scratches. The fundamental reason is the lack of comprehensive understanding of the polishing mechanism. Works such as polishing slurry addings, rogue particles and different slotting methods have been carried out, focused on surface scratch and surface controlling during Nd-doped glass polishing process, shown as follows: Different pH value ceria slurries adjused by oxalic acid and sodium tripolyphate and different size polishing powder are used to polish fused silica glass?K9 glass and Nd-doped glass in one separator on pitch plate. Material removal rates (MRR) of glass polished with various pH value slurries and different size powder, and textures of each sample are characterized. The results show that scratches is most on the surface of Nd-doped glass of all three kinds of glass, and the scratch densities increase with the increase of polishing powder size. The MRR of silicate glass are lower than that of phosphate glass. The removal rates of all three kinds of glass would rise under alkaline condition. The texture of fused silica glass is very small due to silicon oxygen tetrahedron structure; near neutral polishing environment and smaller size powder are useful for the surface polishing process of Nd-doped glass; K9 glass is not suitable for alkaline polishing condition; silica glass can realize ultra smooth process. Slotting experiment results show that the mid-frequency error gradually decreases with the decrease of the spacing between grooves. The results also show that the optics polished by square shape groove is easier to get a smaller mid-frequency error than that by circular shape groove. Based on Preston formula, theoretical simulations focus on the effects of slotting methods on mid-frequency errors. The simulation results show that the ring structure of polished glass left by circular groove will produce mid-frequency error after mid-frequency filtering. That glass polished by square groove is easy to suppress mid-frequecy errors and gets a smaller rms value can be seen from the PSD curve. In order to study the effects of different rogue particles on the scratches, and establish the relationship between the rogue particle size and the scratch topography, experiments have been carried out. During the process of phosphate neodymium polishing, three different sizes of corundum, cerium oxide agglomerate and polished powder are introduced as rogue particles. Data of scratch topography are analyzed statistically. The results show that brittle scratches, plastic scratches and mixed scratches all exist, among which brittle scratches account for a large proportion; scratches caused by cerium oxide agglomerate and polished powder are shallow and few, while scratches caused by corundum are deep and many; the scratch density and scratch length caused by corundum of different size increase with the increasing of particle size; distribution of scratch widths caused by different size corundum is similar to the distribution of the size of rogue particle, shown as Gaussian distribution. The width and length of scratches increase with the increasing of rogue particle size.
语种	中文
内容类型	学位论文
源URL	[http://ir.siom.ac.cn/handle/181231/16933]
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	曹俊. 钕玻璃环抛加工工艺研究[D]. 中国科学院上海光学精密机械研究所. 2015.

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