光学元件表面污染对负载能力影响的研究

发布时间：2018-03-25 04:17

本文选题：污染　切入点：光学元件　出处：《电子科技大学》2016年博士论文

【摘要】：负载能力是衡量大型高功率固体激光装置综合性能的重要技术指标之一,持续提高光学元件及薄膜的抗激光辐照损伤能力,是装置负载能力提升的基础。然而,目前激光诱导元件表面损伤仍然是制约装置通量提升的“瓶颈”,而光学元件表面污染在激光诱导元件损伤中扮演着重要的角色。本文针对光学元件表面污染对激光装置负载能力影响这一问题,提出了对大型激光装置内污染物的监测和取样方案,并分析了污染物的成分。实验上系统地研究了各类污染物对光学元件裸片及溶胶-凝胶薄膜的光学性能和抗激光损伤性能的影响,各类污染物沉积量与元件激光损伤阈值之间的关系,元件在特定污染情况下安全运行的“红线”;理论上模拟了表面污染对激光光场的调制。论文主要研究内容和结果如下:1.根据污染物类型,运用了三种在线监测手段,即在线成像系统、声表面波传感器和微纳光纤传感器。结果表明:在线成像系统适合于监控尺寸大于几十微米的颗粒污染物;声表面波传感器能对分子态有机污染物进行有效监测;而微纳光纤传感器的优势在于监控尺度在微米量级或更小的微粒污染物。2.研究了污染物的取样方法及成分分析。(a)固体颗粒及非蒸发性残留污染物采用擦拭的方法采样,污染物形貌运用扫描电子显微镜观察,成分采用能谱仪进行分析。结果表明:各元件表面污染物的成分主要是有机物、金属及矿物质颗粒。(b)分子态有机污染物采用真空采样罐采样,成分则借助质谱仪进行分析。结果表明:激光装置内的分子态有机物多达数十种,主要是烷烃类、氯烷类和芳香烃类;污染物总含量及各组分浓度随激光发次和作用时间的增加而降低。3.研究了污染物对光学元件裸片(熔石英、K9玻璃)的光学性能及抗激光损伤性能的影响。(a)研究了尘埃颗粒对K9玻璃损伤形貌及激光损伤阈值的影响。尘埃颗粒处损伤坑的尺寸随激光发次、能量的增加而增大;K9玻璃的激光损伤阈值与尘埃尺寸之间呈反比的关系,划出了K9玻璃在不同尺寸尘埃颗粒污染下安全运行的“红线”。(b)研究了真空油对熔石英和K9玻璃表面形貌、透过率、激光损伤阈值、光热弱吸收等性能的影响。结果表明:光学元件裸片被真空油污染后,其表面呈现出微米量级的油滴;熔石英和K9玻璃的透过率/激光损伤阈值均随油污染沉积质量增加而降低,并获得了相应的变化规律及表达式;划出了熔石英和k9玻璃在不同程度油污染下安全运行的“红线”。4.研究了污染物对SiO_2溶胶-凝胶薄膜(1ω和3ω增透膜)的光学性能及抗激光损伤性能的影响。(a)研究了尘埃颗粒对1ω增透膜的损伤形貌和激光损伤阈值的影响。尘埃颗粒处薄膜损伤形貌随激光能量的增加而加剧;1ω增透膜的激光损伤阈值与尘埃尺寸之间呈反比关系,划出1ω增透膜在不同尺寸尘埃颗粒污染下安全运行的“红线”。(b)研究了真空油对溶胶-凝胶增透膜表面形貌、透过率、激光损伤阈值等性能的影响。结果表明:当油污染由轻到重,薄膜表面依次出现油渗透、油斑、凝聚、颗粒状形态;1ω和3ω增透膜的透过率/激光损伤阈值随油污染沉积质量的增加而降低,并获得了相应的变化规律及表达式;划出了1ω和3ωSiO_2溶胶-凝胶增透膜在不同程度油污染下安全运行的“红线”。(c)研究了分子态有机污染物(橡胶管出气)对SiO_2溶胶-凝胶增透膜的光学性能及激光损伤的影响。结果表明:溶胶-凝胶增透膜的透过率及激光损伤阈值随污染时间增加或气压降低而减小。另外,1ω增透膜的抗污染能力比3ω增透膜强;在薄膜遭受较严重污染时,透射峰值会出现红移。5.建立了椭球颗粒、圆锥颗粒、圆柱颗粒及膜层污染的三维模型,采用三维时域有限差分(3D-FDTD)方法和完全匹配层(PML)吸收边界条件,针对各类污染物对激光光场的调制进行了数值模拟,得到了污染物参数(形状、位置、尺寸、相对介电常数、颗粒数、间距)与激光光场调制的关系,并给出了相应电场峰值的变化规律。上述结果表明,针对光学元件表面污染对负载能力影响的研究,无论是实验研究还是数值模拟都的取得了较大的进展。对工程上(激光系统)有一定的参考价值和指导意义。
[Abstract]:Load capacity is one of the most important indexes to measure the comprehensive performance of high power solid-state laser device, continuously improve the ability of anti laser irradiation damage of optical elements and films, is the basic unit in increasing the load capacity. However, the laser induced surface damage element is still restricting device upgrade flux "bottleneck", and the optical element in the surface pollution laser induced damage plays an important role in this paper. The optical element surface pollution elements on the laser device affect the load capacity of this problem, proposed to the large-scale laser facility in pollutant monitoring and sampling scheme, and analyzes the effects of pollutants in the experiment. A systematic study of the optical properties of various pollutants on the optical element chip and sol gel film and the anti laser damage performance, the relationship between various pollutants deposition and laser damage threshold element In particular, the safe operation of pollution elements under the "red line"; simulated surface contamination of the modulated laser light field. The main research contents and results are as follows: 1. according to the type of pollutants, using three kinds of online monitoring methods, namely online imaging system, the surface acoustic wave sensor and micro nano optical fiber sensor. Show that the online imaging system suitable for monitoring pollutant particles size greater than tens of microns; surface acoustic wave sensor for monitoring the molecular state of organic pollutants; sampling methods of particulate pollutants monitoring.2. scale on the order of microns or less of the pollutant and composition in micro nano optical fiber sensor. The advantages of solid particles and (a) non evaporation of residual contaminants by wiping sampling, pollutant morphology by scanning electron microscopy observation, can analyze the component results of spectrometer. Ming: the components of surface contamination is mainly composed of organic compounds, metal and mineral particles. (b) molecular state of organic pollutants by vacuum canister sampling, composition by mass spectrometer were analyzed. The results showed that the molecular state of organic laser device in the dozens, if the main alkanes, alkyl and aromatic chloride hydrocarbons; total pollutant content and concentration of each component increases with laser time and time and reduce.3. of pollutants on the optical element chip (Rong Shiying, K9 glass) influence the optical properties and anti laser damage performance. (a) on the effect of dust particles on K9 glass damage morphology and damage threshold the dust particles damage. The pit size increases with the laser energy, increases; was inversely proportional to the relationship between the laser damage threshold and the dust size of K9 glass, K9 glass made in different sizes of dust pollution Under the safe operation of the "red line". (b) the effects of vacuum oil on quartz and K9 glass surface morphology, transmittance, laser damage threshold, thermal effect of weak absorption performance. The results show that the optical element chip is vacuum oil pollution, the surface shows the micron droplet; fused silica and K9 glass transmittance / laser damage threshold with oil pollution deposition quality increased, and obtained the change rule and the corresponding expression; out of quartz and K9 glass in different degree of oil pollution under the safe operation of the "red line".4. of pollutants on SiO_2 sol-gel films (1 and 3. Omega) antireflection film influences the optical properties and the anti laser damage performance. (a) affected the damage morphology and laser damage threshold of dust particles on the 1 Omega antireflection film on the film. The increase of dust particles damage morphology with laser energy increases; 1 Omega antireflection film The inverse relationship between the laser damage threshold and the dust size, set aside 1 Omega antireflection film in the safe operation of dust particles of different size under the "red line". (b) the effects of vacuum oil on sol gel antireflective film surface morphology, transmittance, laser damage threshold properties. The results show that when the oil pollution from light to heavy, thin film surface followed by oil permeability, oil slicks, condensed, granular shape; 1 W and 3 W antireflection film transmittance / laser damage threshold with the increase of oil pollution deposition quality decreased, and obtained the change rule and the corresponding expression; set aside 1 omega and 3 Omega SiO_2 sol gel antireflective film in different degree of safe operation of oil pollution under the "red line". (c) to study the molecular state of organic pollutants (rubber outlet) antireflection film optical properties and laser damage effects on SiO_2 sol gel. The results showed that the sol gel antireflective film The transmittance and the laser damage threshold of pollution with time increasing or decreasing air pressure decreases. In addition, 1 Omega antireflective film with anti pollution ability than 3 Omega antireflection film; in the film suffered serious pollution, the transmission peak will appear red shift of.5. established ellipsoidal particles, conical particles, three-dimensional model of cylindrical particles and membrane pollution by using 3D finite-difference time-domain (3D-FDTD) method and the perfectly matched layer (PML) absorbing boundary conditions for various pollutants to simulate the modulated laser light field and the pollutant parameters (shape, position, size, relative dielectric constant, particle number, spacing and modulation of the laser light) field, and gives the corresponding variation of the peak of the electric field. The results showed that the research on influence of optical elements on the surface pollution load capacity, both experimental studies and numerical simulation of has made great progress on the project. (laser system) has certain reference value and guiding significance.

【学位授予单位】：电子科技大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：O484.41;TN249

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