1 中北大学省部共建动态测试技术国家重点实验室，山西 太原 030051
2 内蒙古动力机械研究所，内蒙古 呼和浩特 010010
采用355 nm全固态紫外纳秒脉冲激光器对蓝宝石（Al2O3）进行打孔实验。通过控制变量法，对蓝宝石样品进行了打孔加工，研究了激光能量密度、重复频率和扫描速度对蓝宝石通孔质量的影响。实验结果表明，通孔边缘熔融物堆积形成的重凝区随着激光单脉冲能量的升高而减小，但是激光能量过高时，通孔附近出现沉积物，影响通孔的质量；通孔边缘的重凝区随着激光重复频率的降低而减小；通孔附近的沉积物随着激光扫描速度的降低而减少，但是速度过低时，激光脉冲的重叠率过高，导致高斯激光外围孵化效应明显，且其能量不足以使材料气化，因此扫描速度过小时孔道边缘再次出现熔融物堆积形成的重凝区。研究结果表明，采用纳秒脉冲激光加工高质量蓝宝石微通孔是可行的。
激光技术 蓝宝石通孔 控制变量法 全固态紫外纳秒激光 激光烧蚀
Author Affiliations
Abstract
1 Key Laboratory on High Power Laser and Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai201800, China
2 Shanghai Institute of Laser Plasma, China Academy of Engineering Physics, Shanghai201800, China
As the key part for energy amplification of high-power laser systems, disk amplifiers must work in an extremely clean environment. Different from the traditional cleanliness control scheme of active intake and passive exhaust (AIPE), a new method of active exhaust and passive intake (AEPI) is proposed in this paper. Combined with computational fluid dynamics (CFD) technology, through the optimization design of the sizes, shapes, and locations of different outlets and inlets, the turbulence that is unfavorable to cleanliness control is effectively avoided in the disk amplifier cavity during the process of AEPI. Finally, the cleanliness control of the cavity of the disk amplifier can be realized just by once exhaust. Meanwhile, the micro negative pressure environment in the amplifier cavity produced during the exhaust process reduces the requirement for sealing. This method is simple, time saving, gas saving, efficient, and safe. It is also suitable for the cleanliness control of similar amplifiers.
active exhaust and passive intake computational fluid dynamics cleanliness control disk amplifier High Power Laser Science and Engineering
2020, 8(4): 04000e45
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
重复频率激光放大器是实现重复频率激光器的关键器件,其重复频率取决于对抽运及放大过程中产生热量的有效控制。针对千焦耳量级输出重复频率激光器的需求,通过合理的结构设计、冷却液选型及测试等,研制出一台基于氙灯抽运、钕玻璃增益介质、液体冷却、通光直径为Φ130 mm的激光放大器样机。测试结果表明,该放大器样机可实现每分钟一次的重复频率运行,同时具备双程1.3189倍净增益,双程动态波前PV(peak to valley)平均值为0.2718波长(λ)(20 ℃,λ=1053 nm,10发次计)和0.3223λ(30 ℃,λ=1053 nm,10发次计)。
激光器 重复频率激光放大器 液体冷却 氙灯抽运 钕玻璃 中国激光
2019, 46(10): 1001007
Author Affiliations
Abstract
1 National Laboratory on High Power Laser and Physics, Shanghai 201800, China
2 Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
3 Shanghai Institute of Laser Plasma, Chinese Academy of Engineering and Physics, Shanghai 201800, China
In this paper, we review the status of the multifunctional experimental platform at the National Laboratory of High Power Laser and Physics (NLHPLP). The platform, including the SG-II laser facility, SG-II 9th beam, SG-II upgrade (SG-II UP) facility, and SG-II 5 PW facility, is operational and available for interested scientists studying inertial confinement fusion (ICF) and a broad range of high-energy-density physics. These facilities can provide important experimental capabilities by combining different pulse widths of nanosecond, picosecond, and femtosecond scales. In addition, the SG-II UP facility, consisting of a single petawatt system and an eight-beam nanosecond system, is introduced including several laser technologies that have been developed to ensure the performance of the facility. Recent developments of the SG-II 5 PW facility are also presented.
high-power laser facility inertial confinement fusion solid-state amplifier High Power Laser Science and Engineering
2018, 6(4): 04000e55
Author Affiliations
Abstract
National Laboratory on High Power Laser and Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Science, Shanghai 201800,China
Amplified spontaneous emission (ASE) causes the decrease of the inverted population density and the nonuniformity of gain in slab amplifier for high power laser systems. In this paper, a three dimension model, based on the data in SG-II, in which the residual reflection in the cladding and the ASE process are taken into consideration, is built to analyze the space distribution and time evolution of small signal gain coefficient using Monte Carlo algorithm and ray tracing. This model has been verified by comparing with the experimental data. The traverse size of slab is 68.2cm×36.3cm, which is usually decided by the clear aperture and the manufacture. By means of the model, the impact of thickness, residual reflectivity and the stimulated cross section of neodymium glass to the ASE are analyzed in detail.
laser amplifier amplified spontaneous emission Monte Carlo small signal gain coefficient gain uniformity Collection Of theses on high power laser and plasma physics
2016, 14(1): 9255
Author Affiliations
Abstract
1 中国科学院上海光学精密机械研究所, 上海 201800
2 中国科学院大学, 北京 100049
A model which can simulate the pump dynamics process of the main amplifiers in million joules laser facility is built based on Monte Carlo algorithm and a ASAP software. The model contains 3D airspace and 1D time domain, and the evolution of the distribution of the energy in light pass surface in different pumping time with complete absorption on cladding is calculated, which is the same with the results mentioned in previous articles proving the accuracy of the model. The comparisons of average small signal gain coefficient are made between the cases when the residual reflection in cladding is taken into consideration or not. The results show that there is no significant difference when residual reflectivity is below 0.05%. The value of calculated average small signal gain coefficient with residual reflection is 6 percentage smaller than the measured value(4.42/m), which results from the use of part approximation during the simulation, the unconsidered spectrum of spontaneous radiation,the subsurface damage in the actual Nd:phosphate glass and so on.
激光器 激光放大器 放大自发辐射 蒙特卡罗 光线追迹 增益空间分布 lasers laser amplifiers amplified spontaneous emission Monte Carlo ray tracing gain spatial distribution Collection Of theses on high power laser and plasma physics
2016, 14(1): 0214003
Author Affiliations
Abstract
1 Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
2 University of Chinese Academy of Sciences, Beijing 100049, China
The processing method applied to the side surface is different from the method applied to the light pass surface in neodymium phosphate glass (Nd:glass), and thus subsurface defects remain after processing. The subsurface defects in the side surface influence the gain uniformity of Nd:glass, which is a key factor to evaluate the performance of amplifiers. The scattering characteristics of side subsurface defects were simulated by finite difference time domain (FDTD) Solutions software. The scattering powers of the glass fabricated by a computer numerical control (CNC) machine without cladding were tested at different incident angles. The trend of the curve was similar to the simulated result, while the smallest point was different with the complex true morphology. The simulation showed that the equivalent residual reflectivity of the cladding glass can be more than 0.1% when the number of defects in a single gridding is greater than 50.
cladding cladding FDTD FDTD gain uniformity gain uniformity subsurface defect subsurface defect High Power Laser Science and Engineering
2016, 4(1): 010000e9
1 中国科学院上海光学精密机械研究所, 上海 201800
2 中国科学院大学, 北京 100049
基于蒙特卡罗算法及ASAP 光学软件构建了完整分析万焦耳级激光主放大器抽运动力学过程的模型。该模型包含三维空域和一维时域，分析计算了包层完全吸收时不同抽运时刻通光面上的储能分布，其变化趋势与文献报道结果相同，验证了建模的正确性。通过对比包层完全吸收和部分剩余反射时的平均小信号增益系数，发现当剩余反射率低于0.05%时，两者区别并不明显。考虑包层部分反射后平均小信号增益系数的计算值比测量值4.42/m 偏小6%，分析其原因主要在于模型计算过程中的采用部分近似、未考虑自发辐射的光谱宽度以及钕玻璃中存在的亚表面缺陷等。
激光器 激光放大器 放大自发辐射 蒙特卡罗 光线追迹 增益空间分布
山西大学物理电子工程学院, 山西 太原 030006
采用二维时域有限差分(FDTD)法，分析并对比了弯曲分叉部分的形状分别为正弦形和圆弧形的基于金属绝缘体金属（MIM）型表面等离子体光波导的Y形分束器的反射率、传输率以及能量分束比随几何结构参数的变化关系。数值计算表明，波导宽度对这两种Y形分束器传输特性的影响较为明显，两个输出分支的偏移量和弯曲分叉部分的长度对这两种Y形分束器传输特性的影响比较微弱。在600~1500 nm波长范围内，弯曲分叉部分为圆弧形的Y形分束器的传输特性比弯曲分叉部分为正弦形的好。对于非对称型Y形分束器，当弯曲分叉部分为正弦形时，偏移量对反射率、传输率和能量分束比的调节作用较为明显，能量分束比最大可达到2∶1。当弯曲分叉部分为圆弧形时，偏移量对反射率、传输率和能量分束比的调节作用较为微弱。
集成光学 光波导 表面等离子体光波导 Y型分束器
