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题名	光学薄膜元件表面形貌的表征与控制
作者	胡达飞
学位类别	硕士
答辩日期	2010
授予单位	中国科学院上海光学精密机械研究所
导师	易葵
关键词	光学薄膜 面形指标 表面粗糙度 功率谱密度
其他题名	The Metrology and Control of Optical Coatings’ surface
中文摘要	用于惯性约束聚变(ICF) 的高功率固体激光装置大多采用多路大口径结构，这种光学系统具有通光口径大、光学性能好、承载激光束功率高的特点。多路光学系统将使用大量的精密光学元件，高面形精度、超光滑表面、高损伤阈值以及大口径构成了对光学元件的综合要求。有别于传统的光学成像系统，惯性约束聚变激光系统要求对光学元件的波前质量进行全空间频段的控制。 光学元件低频段的波前畸变误差将直接决定激光束的焦斑质量, 可用全口径透射或反射波前畸变及波前位相梯度来描述这一段的质量要求。光学元件的高频波纹调制不但会造成焦斑旁瓣, 还会引起非线性自聚焦破坏, 降低激光损伤阈值和增加散射损耗, 因此也应严格控制。中频段空间频率成分将导致光束的波前调制与系统噪声的非线性增长, 造成光学元件的丝状破坏和降低光束的可聚焦功率, 应用功率谱密度（PSD）来描述这一段的质量要求。 本文首先对评价面形的参数定义及其测量方法进行了描述，然后对低频评价参数峰谷值（PV）与均方根梯度（GRMS）值之间的关系、GRMS与PSD及PSD与均方根（RMS）之间的关系从理论上进行了研究，并通过实际镀膜元件的检测结果对其中一些对应关系进行了验证。发现GRMS与PV存在一定的线性关系；对于频域评价参数PSD和空域评价参数RMS两者联系如下：对于某特定频段的PSD，它的积分恰是该频段RMS的平方，因此，PSD完全能够提供RMS的相关信息。 另外，在确定了镀膜光学元件各频段评价参数之间的关系基础上，通过实验对RMS和PSD的影响因素及可能控制途径进行了实验研究，结果发现镀膜过程的氧分压控制对元件镀膜后的PSD值有较大影响，与基片PSD相比，镀膜后PSD表现出上升趋势，这主要是因为镀膜过程使得基底形貌的各向异性更加明显，表明可以通过调整工艺参数的方法来对PSD进行控制。
英文摘要	The high power solid-state laser system used in the Inertial Confinement Fusion(ICF) is composed by multiple large-diameter optical struction with the characteristics of large optical aperture, good optical performance, bearing the high power of laser beam. Hence it leads to much more stricter detail requirement to the optical components, such as the high surface metrology accuracy, super-smooth surface, high damage threshold and large diameter optical components. Intertial confinement laser syetem requires the control of the wavefront of optical components in the whole frequency band, which is different from the traditional optical imaging systems. Optic’s wavefront distortion of low frequency will directly influence the quality of the laser beam focal spot, it can be described by the transmitted or reflected wavefront aberration and the phase gradient of wavefront. The high spatial frequency ripple of optical components will cause the side lobe of focal spot, lower the laser damage threshold and increase the scattering loss, so it should be strictly controlled. The mid spatial frequency will bring the wavefront modulation and the nonlinear growth of the noise, which will result in the damage of optical components and lower the beam power. The Power Spectral Density(PSD) is the most effective specification for controlling the mid spatical frequency errors. The relationship between evaluation parameters of surface metrology has been studied theoretical. We found that the Gradient of Root Mean Square(GRMS) increased with the increase of the Peak to Valley(PV), which also can be confirmed from experiment. The PSD and Root Mean Square(RMS) are the specification of frequency and space separately. Within a particular spatial frequency band, we can calculate the RMS wavefront error integrating the PSD over that. After the analysis of the relationship between those specification, we carried out experiment to find out the dominating factor in the coating process. The result showed that the oxygen partial pressure has great effect on the PSD, compared with the substrate, the PSD of coating showed an upward trend, which was mainly caused by the anisotropy of the substrate topography introduced in the coating process. Therefore, we can improve the PSD specification by control coating process.
语种	中文
内容类型	学位论文
源URL	[http://ir.siom.ac.cn/handle/181231/16673]
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	胡达飞. 光学薄膜元件表面形貌的表征与控制[D]. 中国科学院上海光学精密机械研究所. 2010.

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