K9玻璃具有硬度高、 热稳定性好、 膨胀系数小以及较高的透过率等特性, 被广泛应用在高功率激光领域。 光学元件污染物诱导损伤问题成为限制高功率激光器发展的瓶颈之一, 深入研究光学元件的损伤机理对于控制损伤的形成具有重要意义。 为探究损伤机理, 利用光谱探测分析对Al2O3诱导K9玻璃激光损伤的机制进行了研究。 即采用EDS能谱探测技术对损伤前后损伤形貌及元素原子百分比变化进行探究, 进而了解损伤过程中发生的物理变化及烧蚀化学变化, 并结合LIBS技术对损伤过程中的电离过程进行诊断和讨论。 实现了对光学元件损伤原理的探究以及光学元件安全的实时监测。 研究结果表明, 在激光诱导污染物至K9玻璃损伤的过程中, Al2O3颗粒形貌发生变化, K9玻璃也有微形损伤坑的出现。 此外, Al2O3颗粒元素原子百分比含量由于颗粒的变形而发生改变, K9基底中含有的Na2O与氧气结合造成了O元素原子百分比含量升高, SiO2会发生气化-凝结成超细颗粒导致Si元素原子百分比的降低。 这些变化直接反映了在损伤过程中发生了高温熔融现象。 电离击穿过程可以采用LIBS进行检测, 得到在损伤过程中有等离子体闪光的特性。 对上述物理过程进行了建模仿真研究, 使用COMSOL模拟分析了在损伤过程中的热传导以及等离子体冲击波在基底内的传播特性。 研究表明在发生损伤的过程中颗粒的温度达到2 800 K高于自身的熔点(2 313 K), 同样, 基底的温度(2 500 K)也高于自身的熔点(1 673 K), 这直接引起相变, 并在后续激光辐照下产生等离子体, 等离子体的高压冲击等作用致使基底微型熔融损伤坑的出现。 模拟分析验证了LIBS技术和EDS能谱分析探究光学元件损伤机制的可行性和准确性, 该方法既可以用于损伤机理的分析, 还可以对高功率激光系统稳定运行实施监测。

实验研究了纳秒激光辐照下不同材料的工程陶瓷表面的抗激光损伤能力, 并与不锈钢、铝合金等金属材料进行了对比.结果表明, 不同材料的工程陶瓷表面抗激光损伤特性不同; 氧化铝陶瓷的损伤阈值最高, 氮化硅陶瓷的损伤阈值较低.与金属材料相比较, 工程陶瓷表面损伤阈值比不锈钢和铝合金高.由于材料的熔点和热传导率等热力学特性不同, 不同的陶瓷材料具有不同的损伤阈值和损伤形貌.理论分析了不同材料抗激光损伤阈值的差异; 陶瓷材料的吸收系数远远小于金属材料, 吸收系数通过影响能量沉积区域和有效热扩散速率影响材料温度的演化过程, 最终影响着材料的激光损伤阈值和损伤特性.实验结果为高功率激光装置中对抗激光损伤能力要求较高的机械支撑材料的选择提供了指导.

为了充分利用高光谱图像中包含的空间信息, 将一种改进的双边滤波应用到其目标检测中, 提出基于光谱角匹配的双边滤波稀疏表示高光谱目标检测算法。通过将光谱角匹配与双边滤波相结合, 用高光谱图像像元之间的相似性作为双边滤波器中值域距离的权值, 在抑制了图像各波段中噪声的同时突出了目标, 然后通过稀疏表示算法进行目标检测。实测的高光谱数据实验显示, 与传统稀疏表示方法和普通双边滤波稀疏表示方法比较, 所提方法在检测效果上有一定的提高。证明了充分利用高光谱图像的空间信息能进一步提高其目标检测的效果。

传统基于可视域分析方法获得的地面站信号覆盖常常无法准确反映系统的实际监视性能。提出一种针对不规则地形的广播式自动相关监视(ADS-B)地面站信号覆盖分析方法。首先针对不规则地形信道特点, 推导了Longley-Rice模型的具体仿真算法, 提出利用该模型模拟航空无线信道; 仿真符合ADS-B规范标准的天线, 计算信号在自由空间的辐射距离; 然后结合由地物遮挡引起的视线截止距离, 进行综合比较得出最终覆盖范围; 最后选取某地为例进行研究和分析, 与其他算法比较, 用实际数据对预测范围进行验证。实验结果表明, 不规则地形是影响地面站覆盖的关键因素, Longley-Rice模型可以准确模拟信号衰减。本文方法为地面站选址提供理论支持。

光谱匹配对光谱曲线的稳定性和准确性均有严格要求，而高光谱图像数据中的光谱曲线受多种因素影响。对此，以平场域法为基础，设计了自动搜索平场域策略，并结合黑暗像元法和其他研究领域常用的经验法，提出一种改进的高光谱图像预处理方法，实现了基于高光谱图像本身数据的自动反射率反演。使用3幅各具特点的图像数据进行的实验表明，本文方法比传统的内部平均法和平场域法有更强的准确性和鲁棒性，能有效改善光谱匹配的效果。

In order to monitor the volatilization and deposition of organic contaminants on optics surfaces in high power laser facility, online detection of airborne molecular contaminant was investigated based on quartz crystal microbalance and optical microfiber. First, the response performance of quartz crystal microbalance for different densities of airborne molecular contamination was tested. Then the comparison of quartz crystal microbalance and optical microfiber in detecting the surface mass density of airborne molecular contamination was implemented with the view factor method. The characteristics of airborne molecular contamination deposited on optical surface were also studied. The experiment results show that quartz crystal microbalance and optical microfiber have the similar response performance, and thus they can be applied in online airborne molecular contamination detection. When the surface mass density of airborne molecular contamination is larger than 0.5×10－5g/cm2, optical microfiber is preferred due to the higher precision and larger response speed. The more the density of airborne molecular contamination is, the more it deposits on the optics.

In order to monitor the volatilization and deposition of organic contaminants on optics surfaces in high power laser facility, online detection of airborne molecular contaminant was investigated based on quartz crystal microbalance and optical microfiber. First, the response performance of quartz crystal microbalance for different densities of airborne molecular contamination was tested. Then the comparison of quartz crystal microbalance and optical microfiber in detecting the surface mass density of airborne molecular contamination was implemented with the view factor method. The characteristics of airborne molecular contamination deposited on optical surface were also studied. The experiment results show that quartz crystal microbalance and optical microfiber have the similar response performance, and thus they can be applied in online airborne molecular contamination detection. When the surface mass density of airborne molecular contamination is larger than 0.5×10－5g/cm2, optical microfiber is preferred due to the higher precision and larger response speed. The more the density of airborne molecular contamination is, the more it deposits on the optics.

Based on the vibration theory and the matrix optics theory, the principle of the optical image method to test the beam positioning stability is derived. The test method of beam positioning stability is designed, and the experimental results show that the optical image method can accurately analyze the range of the beam positioning stability error, also can analyze the value and influence degree of vibration frequency of the error, and combined with the accelerometer by the electron test method, the source of the error can be detected in the optical system. The optical-electro test method is reliable, simple and convenient, and has good engineering application value, especially for large optical system.

To overcome the problem of cleanliness in the laser′s internal cavity, a glass cavity design for a Nd: glass slab amplifier was proposed, which uses UV-stop quartz glass for its main structure.The design of the main structure of the glass cavity and the sealing are optimized, and metal-coated surfaces are used to prevent light from escaping.The cleanliness of the stainless steel cavity of the slab amplifier of the SG-II-UP laser and the glass cavity of a 100 slab amplifier were compared; the cleanliness of the glass cavity was found to be 70% better than that of the stainless cavity. Further, advanced system analysis program was used to simulate the designed amplifier, with the pumping ratio of the Nd: glass in the glass cavity being increased by 8.84%.Thus, the glass cavity decreases the production of aerosols and enhances the pumping ratio of the Nd∶glass.

To overcome the problem of cleanliness in the laser′s internal cavity, a glass cavity design for a Nd: glass slab amplifier was proposed, which uses UV-stop quartz glass for its main structure.The design of the main structure of the glass cavity and the sealing are optimized, and metal-coated surfaces are used to prevent light from escaping.The cleanliness of the stainless steel cavity of the slab amplifier of the SG-II-UP laser and the glass cavity of a 100 slab amplifier were compared; the cleanliness of the glass cavity was found to be 70% better than that of the stainless cavity. Further, advanced system analysis program was used to simulate the designed amplifier, with the pumping ratio of the Nd: glass in the glass cavity being increased by 8.84%.Thus, the glass cavity decreases the production of aerosols and enhances the pumping ratio of the Nd∶glass.