中国科学院上海光学精密机械研究所高功率激光物理联合实验室，上海 201800
高功率激光装置是一个复杂的有源巨型光学工程，其性能指标要求逼近科学技术与物理极限。驱动器研制有物理设计、工程光学和结构工程设计三大过程，工程光学在其中起着重要作用。高功率激光装置工程光学设计需遵循其特有的设计原则和要点，以保证装置的高性能。根据驱动器设计指标和设计特点，从总体光学设计、光束质量控制以及光束打靶精度控制方面，综述了高功率激光装置工程光学设计中的关键科学技术问题以及相应解决方法，为未来高功率激光驱动器的发展提供必要的工程设计参考。
光学设计 惯性约束聚变 神光装置 工程光学 激光光学
1 中国科学院大学工程科学学院, 北京 100049
2 中国科学院力学研究所先进制造工艺力学重点实验室, 北京 100190
3 河北科技大学理学院, 河北 石家庄 050080
轮轨黏着系数对于列车运行的安全性与稳定性具有决定性的影响。在冬季, 钢轮表面的薄冰会大幅降低轮轨黏着系数。根据水的相图和压力融化原理, 将轮轨接触区域划分为钢-冰固体接触区和钢-水混合润滑接触区, 基于统一雷诺方程模型, 研究了温度在-21 ℃至0 ℃, 运动速度为100~500 km/h范围内, 高速轮轨黏着系数随速度的变化规律, 并提出采用激光毛化技术在车轮表面形成规则形貌(纵纹、横纹、菱形), 将有助于提高冰水混合润滑状态下的轮轨黏着系数, 为高速列车黏着控制技术提供理论基础。
弹流润滑 表面形貌 激光毛化 黏着系数 elasto-hydrodynamic lubrication surface topography laser texturing adhesion coefficient
Author Affiliations
Abstract
Key Laboratory on High Power Laser and Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
The objective of maintaining the cleanliness of the multi-segment disk amplifier in Shenguang-II (SG-II) is to reduce laser-induced damage for optics. The flow field of clean gas, which is used for the transportation of contaminant particles, is a key factor affecting the cleanliness level in the multi-segment disk amplifier. We developed a gas–solid coupling and three-dimensional flow numerical simulation model. The three-dimensional and two-phase flow model is verified by the flow-field smog experiment and the particle concentration measurement experiment with the 130-disk amplifier in SG-II. By optimizing the boundary conditions with the same flow rate, the multi-inlet vector flow scheme can not only effectively reduce the purging time, but also prevent the reverse diffusion of contaminant particles in the multi-segment disk amplifier and the deposition of contaminant particles on the surface of the Nd:glass.
cleanliness computational fluid dynamics flow field multi-segment disk amplifier vector flow High Power Laser Science and Engineering
2018, 6(1): 010000e1
1 中国科学院上海光学精密机械研究所高功率激光物理联合实验室, 上海 201800
2 中国工程物理研究院上海激光等离子体研究所, 上海 201800
高功率片状放大器在线运行时氙灯辐照导致片腔内产生大量气溶胶，易引起钕玻璃污染，影响其使用寿命。采用洁净氮气吹扫恢复片腔内的洁净环境是片状放大器在线运行时的主要洁净手段。研究了氮气吹扫过程中片腔内涡流对洁净度的影响，结果显示涡流对气溶胶颗粒的禁锢作用会导致腔内气溶胶颗粒的大量残留，且无法通过延长吹扫时间或调整吹扫流速加以解决。针对这一问题，提出了间断多次氮气吹扫对腔内气溶胶进行循环稀释的在线洁净控制方法，该方法使腔内涡流经历不断破坏和重建过程，涡流场内滞留的气溶胶颗粒含量也得到不断稀释，从而大幅提高片腔洁净度。针对Φ130 mm单口径片状放大器进行了对比实验研究。采用间断吹扫法之后，腔内残留气溶胶颗粒为连续吹扫时的1/100，片腔洁净度在15 h的观测时间内始终保持在40级以内。该方法普适有效，为避免片状放大器钕玻璃气溶胶污染,增加其在线使用寿命提供了重要参考。
激光光学 片状放大器 在线洁净 气溶胶 间断多次吹扫 涡流
1 中国科学院上海光学精密机械研究所高功率激光物理重点实验室， 上海 201800
2 中国科学院大学， 北京 100049
片状放大器腔内钕玻璃表面的洁净度是保证放大器高工作性能和长寿命的关键指标，而合理的腔内流场分布是放大器保持腔内洁净的前提条件。运用计算流体力学方法，利用Fluent软件对纯氮气冲洗片状放大器过程中的腔内流场进行模拟，并在样机上验证了模型的有效性；通过调整放大器的进出气口结构及位置排布，获得了最佳的流场分布。实验结果表明，相比未优化放大器，优化后的放大器仅使用一半时间就可以达到相同的腔内洁净度等级，且钕玻璃表面洁净度更高。
激光技术 片状放大器 计算流体力学 流场模拟 洁净度 优化
Author Affiliations
Abstract
1 National Laboratory on High Power Laser and Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
2 University of Chinese Academy of Sciences, Beijing 100049, China
We propose two technologies to extend the number of layers in order to complete the three-dimensional (3D) array diffraction-limited foci, which means there are two-dimensional array foci at multi-focal planes. One technology is the diffractive optical lever; the other is multi-hybrid Fibonacci structures. Based on the aperiodic Fibonacci structures and binary phase modulation, various kinds of devices can be designed to produce 3D array foci whose focusing properties approximately satisfy the mathematical characteristics of the Fibonacci sequences. With those technologies, the diffraction-limited array foci are freely designed or distributed as required at the desired multiple focal planes.
Collection Of theses on high power laser and plasma physics
2016, 14(1): 060501
Author Affiliations
Abstract
1 National Laboratory on High Power Laser and Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
2 University of Chinese Academy of Sciences, Beijing 100049, China
We propose two technologies to extend the number of layers in order to complete the three-dimensional (3D) array diffraction-limited foci, which means there are two-dimensional array foci at multi-focal planes. One technology is the diffractive optical lever; the other is multi-hybrid Fibonacci structures. Based on the aperiodic Fibonacci structures and binary phase modulation, various kinds of devices can be designed to produce 3D array foci whose focusing properties approximately satisfy the mathematical characteristics of the Fibonacci sequences. With those technologies, the diffraction-limited array foci are freely designed or distributed as required at the desired multiple focal planes.
050.1965 Diffractive lenses 080.2720 Mathematical methods (general) 220.4000 Microstructure fabrication 340.7480 X-rays, soft x-rays, extreme ultraviolet (EUV) Collection Of theses on high power laser and plasma physics
2016, 14(1): 060501
Author Affiliations
Abstract
1 中国科学院上海光学精密机械研究所高功率激光物理重点实验室， 上海 201800
2 中国科学院大学， 北京 100049
The cleanliness of neodymium glass surface in the slab amplifier is a key indicator of guaranteeing high performance and long lifetime of amplifiers, and the reasonable internal flow field distribution is the prerequisite for keeping clean in the amplifier cavity. By means of computational fluid dynamics method and with the Fluent software, the internal flow field of slab amplifier cavity in the purging process of pure nitrogen is simulated, and the model validity is verified on the prototype system. By adjusting the structure and location arrangement of air inlets and outlets of the amplifier, the optimal flow field distribution is obtained. The experimental results show that compared with those of the non-optimized amplifier, the optimized amplifier not only takes only half time to obtain the same required cleanliness, but also the cleanliness of neodymium glass surface is higher.
激光技术 片状放大器 计算流体力学 流场模拟 洁净度 优化 laser technique slab amplifier computational fluid dynamics flow field simulation cleanliness optimization Collection Of theses on high power laser and plasma physics
2016, 14(1): 0901002
1 中国科学院力学研究所先进制造工艺力学重点实验室, 北京 100190
2 北京理工大学机械与车辆工程学院, 北京 100190
为了研究规则分布的表面形貌对轮轨接触在混合润滑状态下摩擦系数的影响，设计了3种不同的表面纹理：横纹、纵纹、菱形。用确定性模型取代平均流量模型，对膜厚、压力、接触面积比进行了数值计算，总的接触载荷由流体接触区和固体接触区分别分担，总的摩擦力等于流体区的摩擦力和固体接触区摩擦力之和。根据设计的3 种表面纹理，用YAG 激光对车轮钢试样表面进行激光毛化处理，获得这3种表面纹理，在RSW-2摩擦磨损试验机上进行油介质条件下的混合润滑摩擦学实验，模拟轮轨间有油污时的工况，测量了该条件下各种表面纹理下的摩擦系数，并与未作激光毛化处理的表面进行对比。理论和实验结果显示，在油介质混合润滑条件下，有激光表面纹理的摩擦系数远大于未作激光毛化处理的试样表面的摩擦系数。3 种激光表面纹理中，菱形纹理的摩擦系数大于纵纹和横纹的摩擦系数，纵纹的摩擦系数比横纹略大。因此，在油污条件下使用激光毛化的菱形纹理表面能较显著地提高轮轨间的摩擦系数。
激光技术 摩擦系数 激光毛化 混合润滑
Author Affiliations
Abstract
Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
The flow field of thermal recovery system in the rod amplifier has significant influence on the laser beam quality. The flow field of the thermal recovery system depends on the inlet and outlet angles of water. Based on the flow field distribution of the direct-flow type for the thermal recovery system, we develop the optimum inlet and outlet angles of the thermal recovery system to the rod amplifier, which enhances the uniformity of the flow field and heat exchange efficiency of the thermal recovery system.
140.3280 Laser amplifiers 140.3580 Lasers, solid-state 140.6810 Thermal effects Collection Of theses on high power laser and plasma physics
2014, 12(1): S21408
