基于光传输的激光驱动器负载能力提升设计研究
文献类型：学位论文
| 作者 | 孙晓艳 |
| 学位类别 | 博士 |
| 答辩日期 | 2016 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 范滇元 |
| 关键词 | 负载能力 颗粒状扰动 损伤机制 规避损伤 |
| 其他题名 | Damage Resistance Improvement of Laser Facilities Based on Optical Transmission |
| 中文摘要 | 在高功率激光驱动器中，激光运行通量通常接近于光学元件损伤阈值，三倍频段的光学元件是最容易发生激光诱导损伤的部分，严重制约着高功率激光驱动器负载能力的提升。其中，三倍频光学元件发生损伤的一个重要原因是：小尺度颗粒污染物调制激光光束而使下游光束产生高光强调制点，这种局部区域的峰值光强超过光学元件损伤阈值时容易诱导光学元件损伤。因此，避免颗粒状扰动光束在传输过程中诱导光学元件损伤非常必要。鉴于颗粒污染物对激光驱动器激光运行通量提升的严重影响，本文从光传输角度研究在终端光学组件中如何降低由颗粒污染物引发的光束质量劣化和光学元件损伤带来的风险。 本文在理论上研究了颗粒状扰动光束线性和非线性传输的物理模型和数值模拟，在实验上验证了颗粒状扰动引起较高光强调制的理论预期，从光传输角度阐明了颗粒状扰动光束诱导光学元件初始损伤的机制，提出了一种规避光学元件初始损伤的策略和方法，并已得到实际应用。此外，还分析了颗粒状扰动对远场焦斑的影响，探讨了3种集束聚焦方案下的靶面光强分布特性。相关创新性研究成果已发表SCI收录论文3篇，EI收录论文1篇，以及申请发明专利一项。 本论文的主要研究内容和创新点有： 1. 理论研究了光学系统中颗粒导致的光束调制演化规律，阐明了诱导光学元件初始损伤的机制。本文研究发现，除元器件本身存在的初始颗粒外，被调制的传输激光还会诱导产生次级颗粒；数值模拟了各类颗粒状扰动光束的线性和非线性传输效应及近场光强调制幅度，解释了光学元件前表面颗粒诱导后续表面损伤的原因和机制。相关内容已发表在物理学报，2014，63(13): 134201。 2. 实验研究了什么样的颗粒污染物容易引起高光强调制。基于颗粒的三种存在状态，获得了实际扰动光束的光强调制规律，检测到了较高光强调制幅度的存在，验证了相关颗粒状扰动模型和诱导损伤机制的合理性。相关内容已发表在Proc. of SPIE，2015, 9532: 953216，并申请了一项发明专利(申请号：201510398980.X)。 3. 提出了一种避免颗粒状扰动光束诱导损伤的策略和方法。合理利用与控制衍射效应，避免光学元件落在颗粒状扰动光束的高峰值强度区，从统计上优化三倍频光学元件的排布和厚度。相关内容已发表在Chinese Physics B，2015, 24(5): 054209，并已实际应用于神光II升级的高功率激光驱动器中。 4. 研究了颗粒状扰动对光束远场的影响，结果表明随着光学元件初始损伤点的快速增长，将引起大面积遮光和高频调制大幅增强，从而造成焦斑能量损失和激光穿孔时的等离子体堵孔。 5. 研究了有助于提升负载能力的远场聚焦方式。基于终端光学组件中的二维离轴透镜、一维离轴透镜和非离轴透镜3类大口径透镜，研究了3种2?2集束聚焦设计方案，分别分析了其波前调制特性，模拟获得了相应的靶面光强分布特性，研究结果为集束聚焦方案的优化提供参考。相关内容已发表在物理学报，2016，65(6)：064203。 |
| 英文摘要 | In high power laser facilities, laser operation flux is usually close to optical element damage threshold, and third harmonic components are the easiest part where the laser-induced damage occur, which severely restrict the damage resistance of high power laser facilities. One of the most important reason that the damage to the third harmonic components are as follows: small scale particles modulate laser beam and make the downstream beam generate localized high peak intensity, and the localized peak intensity higher than optical element damage threshold easily induce damage to optical elements. Therefore, it is very necessary to avoid that the laser beam disturbed by particle contaminations induce damage to optical elements in the transmission process. Given the effect of particle contaminations on the power putout of high power laser facilities, this article researched how to reduce the beam quality degradation caused by particle contaminations and the risk from component damage in final optics assembly from the optical transmission of view. This article theoretically studied the physical model and numerical simulation of linear and nonlinear transmission of the laser beam with granular disturbance, verified the theorized expectations that the granular disturbance cause high intensity modulation in the experiment, from the optical transmission of view illuminated the mechanism that the beam with granular disturbance induce initial damage to optical element, put forward a strategy and method to circumvent the initial damage to optical elements, which has had a practical application. In addition, the article analyzed the effect of granular disturbance on the far field focal spot, discussed the light intensity distribution on the target plane under three focus system of beam array. Some innovative results have been published in domestic and international journals including Chin. Phys. B, Acta Phys. Sin., Proc. of SPIE, and a patent for invention. The main research contents and innovation points of this paper are as follows: 1.The article studied the modulation and evolvement rule of the laser beam caused by particle contamination in the optical system, expounded the mechanism of the induced initial damage to optical elements. The study found that in addition to the initial particles existing in components, the modulated laser beam can induce the secondary particles, simulated numerically the linear and nonlinear transmission effect and the modulation amplitude in near field for the laser beam with all kinds of granular disturbance, explained the reason and mechanism that the particles on the front-surface of the optical element induce the damage to subsequent surfaces. The related content in the paper has been published in Acta Phys. Sin., 2014,63 (13): 134201. 2.The experiment studied what kind of particle pollution is easy to cause the high light intensity. On the basis of three existential state of particles, we obtained the light intensity modulation of the actual disturbed beams, detected the existence of the modulation amplitude with high light intensity, verified the rationality of the relevant theoretical model of granular disturbance and the mechanisms of the induced damage. The related content has been published in Proc. of SPIE, 2015, 9532: 953216, and applied for a patent (application number: 201510398980.X). 3.A strategy and method to avoid the component damage induced by the laser beam was put forward. The configuration and thickness of the third harmonic components were optimized statistically to avoid the optical elements to locate in peak intensity area of the light beam with granular disturbance by reasonably using and controlling the diffraction effect. The relevant content has been published in Chinese Physics B, 2015, 24 (5): 054209, and has set up a practical application in the SG-II upgrading high power laser facility. 4.The effect of granular disturbance on the beam far field was studied. the research results showed that the rapid growth of laser-induced damage in optical elements will cause the shading in a large area and a sharp increase in the high frequency modulation, resulting the energy loss in the focal spot and pinhole closure by excited plasma. 5.The method of focusing in the far field which helps to improve the power output was researched. For the large aperture lenses (two-dimensional off-axis lenses, one-dimensional off-axis lenses and non-off-axis lenses) in final optics assembly, the three focus systems of 2×2 beam arrays were designed, the corresponding wave-front characteristics was analyzed, and the corresponding intensity distribution on the target plane was obtained by the simulation. The research results provided a reference for optimizing the focus system of beam arrays. The related content has been published in Acta Phys. Sin., 2016, 65(6): 064203. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15982]  |
| 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 | 孙晓艳. 基于光传输的激光驱动器负载能力提升设计研究[D]. 中国科学院上海光学精密机械研究所. 2016. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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