1 中国科学院上海光学精密机械研究所强场激光物理国家重点实验室，上海 201800
2 中国科学院大学材料科学与光电工程中心，北京 100049
3 张江实验室，上海 201210
利用百太瓦级激光系统在氖气（Ne）中得到基于高次谐波产生的极紫外脉冲。通过松聚焦结构在13 nm波段产生单级次单脉冲能量为13.5 nJ（13.1 nm波长）和11.1 nJ（13.5 nm波长）的高次谐波辐射，转换效率为和，谐波发散角的半高全宽为0.32 mrad和0.33 mrad。对含时薛定谔方程进行数值求解，得到单原子偶极发射谱，结合麦克斯韦方程组模拟传播效应，同时考虑气体对谐波的吸收效应，理论模拟得到的信号强度随气压和光强的变化趋势与实验结果基本符合。实现相位匹配的谐波光束质量很好，纵向空间分布为高斯型。结合相位匹配条件和空间分布的分析得到了目前激光参数下的最优相位匹配条件。这种基于高次谐波机制的高能量相干极紫外光源在作为自由电子激光的种子光源以及超快非线性实验和半导体工业检测等方面具有广阔的应用前景。
极紫外 高次谐波 相位匹配 空间分布
Author Affiliations
Abstract
1 State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-intense Laser Science, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
2 University of Chinese Academy of Sciences, Beijing 100049, China
3 School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
The plasma mirror system was installed on the 1 PW laser beamline of Shanghai Superintense Ultrafast Laser Facility (SULF) for enhancing the temporal contrast of the laser pulse. About 2 orders of magnitude improvement on pulse contrast was measured on picosecond and nanosecond time scales. The experiments show that high-contrast laser pulses can significantly improve the cutoff energy and quantity of proton beams. Then different target distributions are assumed in particles in cell simulations, which can qualitatively assume the expansion of nanometer-scale foil. The high-contrast laser enables the SULF-1PW beamline to generally be of benefit for many potential applications.
ultraintense laser plasma mirror high-contrast laser proton acceleration Chinese Optics Letters
2023, 21(4): 043802
1 中国科学院上海光学精密机械研究所,上海 201800
2 中国科学院西安光学精密机械研究所,上海 201800
中国激光
2021, 48(23): 2316003
Author Affiliations
Abstract
1 State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
2 School of Physical Science and Technology, ShanghaiTech University, Shanghai 200031, China
3 University of Chinese Academy of Sciences, Beijing 100049, China
4 CAS Center for Excellence in Ultra-intense Laser Science, Shanghai 201800, China
A novel tiled Ti:sapphire (Ti:S) amplifier was experimentally demonstrated with >1 J amplified chirped pulse output. Two Ti:S crystals having dimensions of 14 mm× 14 mm× 25 mm were tiled as the gain medium in a four-pass amplifier. Maximum output energy of 1.18 J was obtained with 2.75 J pump energy. The energy conversion efficiency of the tiled Ti:S amplifier was comparable with a single Ti:S amplifier. The laser pulse having the maximum peak power of 28 TW was obtained after the compressor. Moreover, the influence of the beam gap on the far field was discussed. This novel tiled Ti:S amplifier technique can provide a potential way for 100 PW or EW lasers in the future.
Ti:sapphire crystal tiled Ti:sapphire amplifier chirped pulse Chinese Optics Letters
2021, 19(1): 011401
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
3 Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China
4 Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
5 School of Physical Science and Technology, ShanghaiTech University, Shanghai 200031, China
Beam quality degradation during the transition from a laser wakefield accelerator to the vacuum is one of the reasons that cause the beam transport distortion, which hinders the way to compact free-electron-lasers. Here, we performed transition simulation to initialize the beam parameters for beam optics transport. This initialization was crucial in matching the experimental results and the designed evolution of the beamline. We experimentally characterized properties of high-quality laser-wakefield-accelerated electron beams, such as transverse beam profile, divergence, and directionality after long-distance transport. By installing magnetic quadrupole lenses with tailored strength gradients, we successfully collimated the electron beams with tunable energies from 200 to 600 MeV.
020.2649 Strong field laser physics 110.2970 Image detection systems Chinese Optics Letters
2018, 16(4): 040201
1 南昌大学 国家硅基LED工程技术研究中心, 江西 南昌 330047
2 武汉大学 动力与机械学院, 湖北 武汉 430072
采用实验与理论模拟相结合的方法, 研究了氮化镓基绿光发光二极管(LED)中V坑对空穴电流分布的影响。首先, 实验获得了V坑面积占比不同的3种样品; 然后, 建立数值模型, 使得理论计算的外量子效率(EQE)及电压与实验测试的变化趋势相匹配, 从而确立了所用数值模型的可信性。计算结果显示: V坑改变了空穴电流的分布, 空穴电流密度在V坑处显著增加, 在平台处明显减小。进一步的分析表明: V坑面积占比在0~10%范围内, V坑空穴电流占比与V坑面积占比之间呈近线性增长(斜率为2.06), 但V坑空穴注入在整个空穴注入的过程中仍未占主导。
V坑 氮化镓 绿光LED 空穴电流分布 V-shaped pits GaN green LED hole current distribution
1 同济大学物理科学与工程学院， 上海 200092
2 中国科学院上海光学精密机械研究所强场激光物理国家重点实验室， 上海 201800
3 中国科学院大学， 北京 100049
为了获得高重复频率的飞秒激光脉冲，将突发运行模式引入飞秒碟片再生放大系统中。通过将再生放大器的腔长设计为9.3 m,激光系统输出了接近衍射极限的激光脉冲，且激光脉冲的重复频率为电光调制频率的5倍。在电光调制频率为5 kHz、吸收的抽运功率为98 W的条件下，获得了最高输出功率为10.7 W、光谱半峰全宽为1.18 nm、脉冲宽度为777 fs的双曲正割脉冲输出。再生放大器的光-光转换效率随着电光调制频率的增加而增加，从频率为0.5 kHz时的12.4%增加到频率为5 kHz时的25.3%。激光的输出稳定性在18~20 ℃的温度区间内随着水冷温度的降低而提高，激光系统输出功率的均方根从20 ℃时的0.93%变为18 ℃时的0.52%。该研究结果对于设计具有高重复频率、高功率且性能稳定的飞秒激光系统具有参考价值。
激光光学 半导体抽运激光器 再生放大器 突发运行模式 碟片激光器
Author Affiliations
Abstract
1 School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
2 State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
3 Shanghai Institute of Laser Plasma, Shanghai 201800, China
We report on our high-contrast laser based on high-contrast, high-energy seed injection, low-gain optical parametric chirped pulse amplification (OPCPA), and Nd:glass amplifiers, which can be used as the high-contrast front end of a high-power Nd:glass chirped pulse amplification (CPA) laser system. The energy of the stretched 1053 nm high-contrast seed pulse increases to 60 μJ by optimizing the frequency doubling crystal in the pulse cleaning device. After passing through a two-stage low-gain OPCPA, a 2-pass 2-rod Nd:glass amplifier, and a compressor the amplified pulse of 131 mJ/282 fs is achieved. The third-order correlation scanning measurement shows that the pulse contrast in the tens of ps range is about 10 7–10 8. With the high-contrast seed passing through the stretcher and compressor only, the contrast measurement indicates that the stretching-compressing process leads mainly to the contrast degradation of the amplified pulse.
320.7090 Ultrafast lasers 190.4410 Nonlinear optics, parametric processes 140.3280 Laser amplifiers Chinese Optics Letters
2016, 14(2): 023201
1 中国科学院上海光学精密机械研究所强场激光物理国家重点实验室, 上海 201800
2 中国科学院大学, 北京 100049
给出了单轴晶体ooe,oeo,eoo,eeo,eoe,oee 6 种相位匹配方式相位匹配角的解析公式。其中ooe,oeo,eoo 3 种可以计算共线及非共线情况，eeo, eoe, oee 3 种只能计算共线情况，非共线情况需数值求解，给出了数值求解的方法步骤。研究了双轴晶体折射率在主平面时与单轴晶体折射率的对应关系，利用该对应关系，通过替换折射率的方式求解双轴晶体的相位匹配角度。给出了常见晶体的非共线相位匹配角度图，以供科研人员参考。
激光光学 超短超强激光 光参量放大 相位匹配
1 西安近代化学研究所，陕西 西安 710065
2 南京理工大学化工学院，江苏 南京 210094
利用加拿大BOMEN公司出产的MR-254型红外光谱仪，对固体推进剂羽流的红外辐射特性进行了研究。在分辨率为4 cm-1、测试距离为5 m的条件下，实时测得了含铝改性固体推进剂和NEPE固体推进剂的红外发射光谱图，得到了推进剂在3~5 μm波段内的辐射能数据。采用燃烧产物分子的发射光谱精细结构谱线计算了羽流的温度，探讨了固体推进剂辐射能和温度的影响因素。实验结果表明，采用被动式遥感FTIR光谱可对固体推进剂羽流进行快速、实时的非接触式测量，是一种有效的研究手段。
红外辐射 固体推进剂 羽流 温度 infrared radiation solid propellant plume FTIR FTIR temperature
