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 上海交通大学，IFSA协同创新中心，上海 200240
在光束传输控制中，反馈系统需要具有较高的角度分辨率，以达到自动准直的精度要求，此外还需要具备一定的角视场，以降低对初始安装和调试的精度要求。提出了一种基于双焦透镜的双踪远场自动准直方案，在同一光学系统中实现了高精度和大视场两种角度分辨率的远场图像反馈系统。基于矩阵光学理论对远场图像反馈系统进行数值分析，给出了双焦透镜的等效传输矩阵，并分析了双焦透镜的角度分辨率和视场特性。设计并开展实验对基于双焦透镜的双踪远场自动准直方案进行了性能演示，实验结果表明，高精度下的角度分辨率约为大视场下角度分辨率的6.9倍，与设计值（6.6倍）基本相符。
光学设计 高功率激光 自动准直 远场成像 矩阵光学
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
基于亚纳秒间隔的皮秒激光双脉冲，研究了双脉冲时域整形对K9玻璃表面烧蚀特性的调控规律。当子脉冲间隔为667 ps时，不同形状双脉冲下玻璃表面的烧蚀形貌随激光通量增加的变化规律明显不同，而泵浦通量起着决定性作用。当泵浦通量低于阈值时，双脉冲烧蚀特性基本与单脉冲相似；当泵浦通量在阈值附近时，泵浦脉冲对玻璃表面的微纳米尺度的烧蚀会显著增强探测脉冲的烧蚀效应。当泵浦通量高于1.3倍阈值时，泵浦脉冲在玻璃与空气界面附近产生冲击波，探测脉冲被冲击波的高密度前沿界面反射和干涉，在中心烧蚀区域周围产生了圆环状烧蚀形貌，且圆环分布与探测通量密切相关。双脉冲烧蚀的内径尺寸与泵浦通量相关，而外径尺寸与双脉冲的形状、通量均相关。对比研究了子脉冲间隔为333 ps和667 ps时的等通量双脉冲烧蚀形貌，结果发现：低通量下较小的脉冲间隔可以增强烧蚀效应；高于烧蚀阈值的泵浦脉冲会影响探测脉冲的能量沉积；两种脉冲间隔下环状形貌的不同反映了泵浦脉冲产生的冲击波的传输特性不同。最后基于实验结果讨论了双脉冲序列时域整形进行表面烧蚀调控的物理机制。
激光技术 激光烧蚀 皮秒激光 双脉冲 时域整形 中国激光
2023, 50(12): 1202201
Author Affiliations
Abstract
1 Key Laboratory of High Power Laser and Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
2 Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
Different post-treatment processes involving the use of ammonia and hexamethyldisilazane (HMDS) were explored for application to 351 nm third harmonic generation antireflective ( AR) coatings for high power laser systems prepared by the sol-gel method. According to experimental analysis, the AR coatings that were successively post-treated with ammonia and HMDS at 150°C for 48 h and again heat-treated at 180°C for 2 h (N/H 150 + 180 AR) were relatively better. There were relatively fewer changes in the optical properties of the N/H 150 + 180 AR coating under a humid and polluted environment, and the increase in defect density was slow in high humidity environments. The laser-induced damage threshold of the N/H 150 + 180 AR coating reached (355 nm, 6.8 ns), a value that meets the basic requirements of high power laser systems.
optical materials antireflection coatings sol-gel optics at surfaces laser damage thin films optical properties Chinese Optics Letters
2022, 20(1): 011601
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
振镜作为一种二维扫描器件, 可以实现光学元件不同位置处表面情况在CCD相机上的成像, 利用振镜扫描方式无需移动待检测光学元件和成像系统即可完成大口径光学元件表面损伤的扫描检测,提出了一种基于振镜扫描方式的大口径光学元件表面损伤检测方法。利用该方法对光学元件表面损伤点检测进行了验证实验, 通过在元件表面设置基准点, 利用振镜扫描步数及图像处理技术确定损伤点位置及尺寸, 并与光学显微镜观察到的损伤情况进行对比, 结果显示利用振镜扫描方法对元件表面损伤点位置及尺寸的检测结果与光学显微镜检测结果偏差较小。该检测系统分辨率可达到(2.08±0.015) μm/pixel, 检测范围大于2.5 cm, 水平方向和竖直方向位置坐标检测准确度分别为3.76%和1.37%, 损伤点尺寸检测准确度为6.19%, 能够实现较大尺寸光学元件表面损伤点的高准确性检测。
测量 损伤检测 振镜 扫描 激光诱导损伤
Author Affiliations
Abstract
1 中国科学院上海光学精密机械研究所 高功率激光物理联合实验室, 上海 201800
2 中国科学院大学, 北京 100049
In high power laser beam parameters measurement, attenuation scheme with high rate is key to far-field measurement. The far-field optical measurement system was analyzed and diameter of 95% encircled energy was used as important evaluation criterion of far-field measurement system. Measurement error of far-field optical measurement system and effect of attenuation with high rate on far-field measurement results were analyzed. Principle of attenuation scheme with high rate was established. By changing parameters of high attenuation rate in condition of single parallel plate, a pair of parallel plates and a pair of wedge flaps by Virtual Lab, influence of attenuation on the far-field measurement system was simulated and analyzed deeply. According to measurement system for f=3 000 mm and F=10, best attenuation scheme with high rate is designed. Diameter of 95% encircled energy of far-field image is 45.5 ?滋m, or 3.54 times of diffraction limitation.
高功率激光 远场测量 楔板 衰减 high power laser far-field measurement wedge flap attenuation Collection Of theses on high power laser and plasma physics
2016, 14(1): S106002
Author Affiliations
Abstract
1 中国科学院上海光学精密机械研究所 高功率激光物理联合实验室, 上海 201800
2 中国科学院大学, 北京 100049
In high power laser beam parameters measurement, attenuation scheme with high rate is key to far-field measurement. The far-field optical measurement system was analyzed and diameter of 95% encircled energy was used as important evaluation criterion of far-field measurement system. Measurement error of far-field optical measurement system and effect of attenuation with high rate on far-field measurement results were analyzed. Principle of attenuation scheme with high rate was established. By changing parameters of high attenuation rate in condition of single parallel plate, a pair of parallel plates and a pair of wedge flaps by Virtual Lab, influence of attenuation on the far-field measurement system was simulated and analyzed deeply. According to measurement system for f=3 000 mm and F=10, best attenuation scheme with high rate is designed. Diameter of 95% encircled energy of far-field image is 45.5 ?滋m, or 3.54 times of diffraction limitation.
高功率激光 远场测量 楔板 衰减 high power laser far-field measurement wedge flap attenuation Collection Of theses on high power laser and plasma physics
2016, 14(1): S106002
Author Affiliations
Abstract
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
The development of the optically addressed spatial light modulator (OASLM) was reported. Its structure and working principle was introduced in detail. Meanwhile, the photosensitive response curve, static wave-front distortion and temporal waveform distortion was investigated in detail in the process of experiment. Besides, OASLM was successfully demonstrated in the online experiment. The results show that OASLM not only has the ability to achieve the desired transmittance distribution, but also has no additional effect on the high-power laser system. Finally, the shaping effect of spatial filter in the laser system was analyzed. The result shows that the size of spatial filter was also an important factor which determined the shaping precision when this device was used in high power laser systems.
光束质量 光寻址 液晶 空间光调制器 beam quality optically addressed liquid crystal spatial light modulator Collection Of theses on high power laser and plasma physics
2016, 14(1): 0920001
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联合实验室, 上海 201800
2 中国科学院大学, 北京 100049
3 中国工程物理研究院上海激光等离子体研究所, 上海 201800
Based on the mass fraction of 65% deuterated DKDP crystals, the fourth harmonic conversion of 1053 nm laser is realized under the condition of noncritical phase matching (NCPM). The experimentally measured crystal temperature is 29.4 ℃ and the acceptance angle width of the crystals under the NCPM condition is around 55 mrad. Effects of the deuterated amount and the temperature of the DKDP crystals in the process of NCPM on the fourth harmonic conversion are theoretically analyzed. The relationship between the deuterated amount and temperature and the changing of the fourth harmonic conversion efficiency versus the double frequency light intensity are numerically simulated. These results provide a theoretical basis for the application of fourth harmonic laser in the high power laser system.
非线性光学 四次谐波转换 非临界相位匹配 DKDP晶体 接收角宽 nonlinear optics fourth harmonic conversion noncritical phase matching DKDP crystal angular acceptance Collection Of theses on high power laser and plasma physics
2016, 14(1): 0919002
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
报道了自研的光寻址空间光调制器的最新进展, 介绍了器件工作原理与结构, 并对其光敏响应特性曲线、静态位相波前畸变、透射时间波形畸变的离线测试结果进行了报道, 同时也利用该器件在高功率激光装置上进行了在线测试。结果表明, 该调制器可以根据需求实现所需的强度透过率分布, 而且对高功率激光系统没有引入附加的影响。最后, 结合该调制器的实际使用环境, 分析了激光系统空间滤波器对整形效果的影响, 说明在高功率激光系统中使用该调制器时, 空间滤波器尺寸也是决定光束整形精度的重要因素。
光束质量 光寻址 液晶 空间光调制器 beam quality optically addressed liquid crystal spatial light modulator 红外与激光工程
2016, 45(9): 0920001
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 中国科学院大学, 北京 100049
3 中国工程物理研究院上海激光等离子体研究所, 上海 201800
利用质量分数为65%的掺氘DKDP晶体实现了1053 nm激光在非临界相位匹配(NCPM)条件下的四次谐波转换，实验测得NCPM条件下晶体温度为29.4 ℃、晶体接收角宽约为55 mrad。理论分析了NCPM过程中DKDP晶体掺氘量和温度对四次谐波转换的影响，数值模拟了四次谐波转换过程中晶体掺氘量和温度的关系以及四倍频转换效率随倍频光强的变化，这些结果为四倍频光在高功率激光系统中的应用提供了理论依据。
非线性光学 四次谐波转换 非临界相位匹配 DKDP晶体 接收角宽
