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, China
2 Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, China
3 Zhangjiang Laboratory, Shanghai, China
A multistep pulse compressor (MPC) based on a single-pass single-grating pair (SSGP) is proposed to simplify the entire multi-petawatt (PW) compressor. Only one grating pair with relatively long perpendicular distance is used to generate the same amount of spectral chirp compared with a four-grating main compressor. As SSGP compressor induces the largest spatial chirp, it can introduce the best beam-smoothing effect to the laser beam on the last grating. When considering the diffraction loss of only two gratings, the total compression efficiency of the SSGP compressor is even larger than that of a four-grating main compressor. Furthermore, the wavefront aberration induced by the SSGP compressor can be better compensated by using deformable mirrors; however, it is difficult or complicated to be well compensated in a four-grating compressor. Approximately 50–100 PW laser pulses can be obtained using this SSGP-based multistage-smoothing MPC with a single laser beam.
beam smoothing multistep pulse compressor petawatt single-grating-pair compressor High Power Laser Science and Engineering
2023, 11(1): 010000e4
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，中国科学院超强激光科学卓越创新中心，上海 201800
2 中国科学院大学 材料与光电研究中心，北京 100049
超快超强激光可以在实验室创造出超快时间、超强电场、超强磁场、超高温度及超高压力等多种极端物理实验条件，是当前拓展人类对物质世界认知最强有力的工具之一。在超快超强激光的发展过程中，飞秒四波混频过程在多个方面都发挥着非常重要的作用。本文介绍了飞秒四波混频过程在超快超强激光中近年来的一些进展和应用，系统总结了近年来利用级联四波混频、自衍射效应、瞬态光栅效应、四波光参量放大，以及交叉偏振波产生等飞秒四波混频过程，在宽带高对比度种子激光产生，新颖同心多色涡旋/径向偏振飞秒超快光源构建，“四阶相关仪”等脉冲对比度单发测量仪研制，以及脉冲形状宽度单发测量仪研制等方面的成果与进展。未来，飞秒四波混频过程还可拓展到太赫兹和极紫外等波段，继续为超快超强激光技术的发展做出重要贡献。
四波混频 超快激光 超强激光 脉冲测量 Four-wave mixing Ultrafast laser Ultraintense laser Pulse measurement 光子学报
2022, 51(10): 1014002
1 上海大学物理系，上海 200444
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 中国科学院大学材料科学与光电工程中心，北京 100049
超快激光脉冲形状宽度测量的核心是光谱相位的精确测量。本文提出了一种结合深度学习的自参考光谱干涉(SRSI)方法，并用该方法进行了飞秒脉冲相位的测量。该方法基于针对一维信号的Dense-1D-U-Net神经网络，采用经典的编码-解码网络结构并加入稠密连接和跳跃连接来提高网络的性能。结合SRSI法的特点，本文设计出结合了稠密连接块的Dense-1D-U-Net神经网络。基于大量接近真实光谱相位的模拟光谱相位数据可以发现，基于Dense-1D-U-Net的SRSI算法的计算结果的均方根误差相比传统SRSI算法至少降低一个数量级。与有无稠密连接、跳跃连接的对照组神经网络进行对比，分析了Dense-1D-U-Net的优势。最后用实验测量数据验证了使用模拟数据训练的Dense-1D-U-Net具有计算实验数据的能力。Dense-1D-U-Net神经网络未来可以拓展应用到超快光谱等其他一维信息研究领域。
测量 深度学习 编码-解码 自参考光谱干涉 神经网络 稠密连接
Author Affiliations
Abstract
1 Department of Physics, Shanghai University, Shanghai 200444, 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 Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
An all-reflective self-referenced spectral interferometry based on the transient grating (TG) effect is proposed for single-shot measuring of the amplitude and phase of ultrashort pulses in a broadband spectral range. Except for a thin third-order nonlinear medium, which was used to generate the TG signal, no transmitted optics were used in the proposed device, and few-cycle pulses in a broad spectral range from deep UV to mid-IR can be characterized. With a homemade compact and alignment-free device, a 5.0 fs pulse at 800 nm corresponding to about two cycles and a 14.3 fs pulse at 1800 nm corresponding to less than three cycles were successfully characterized.
transient grating self-referenced spectral interferometry few-cycle laser pulses femtosecond laser pulses measurement Chinese Optics Letters
2020, 18(2): 021202
1 四川大学 电子信息学院 激光微纳工程研究所,成都 610065
2 中国工程物理研究院化工材料研究所,四川 绵阳 621900
研究了熔石英玻璃元件在纳秒激光等离子体冲击波作用下的表面和横截面损伤形貌,利用有限元法模拟了冲击波在熔石英玻璃内部的传播规律,并基于冲击波在玻璃内部的应力分布规律分析了损伤形成机理.研究发现：在冲击波作用下,石英玻璃会受到沿波面方向的压应力和沿波面切方向的拉应力,在这两种力的作用下,造成以激光辐照中心的弧状层状断裂和沿径向的断裂；冲击波的反射叠加还会使局部拉应力增大,造成靠近后表面的损伤.有限元法能够直观地分析等离子体冲击波对光学元件的作用,并分析光学元件在等离子体冲击波下的损伤机理.
激光诱导损伤 激光等离子体 冲击波 熔石英玻璃 有限元分析 Laser induced damage Laser plasma Shock wave Fused silica glass Finite element analysis 光子学报
2019, 48(10): 1030003
Author Affiliations
Abstract
1 Chinese Academy of Sciences, Shanghai Institute of Optics and Fine Mechanics, State Key Laboratory of High Field Laser Physics, Shanghai, China
2 University of Chinese Academy of Sciences, Center of Materials Science and Optoelectronics Engineering, Beijing, China
3 Chinese Academy of Sciences, Shanghai Institute of Optics and Fine Mechanics, CAS Center for Excellence in Ultra-intense Laser Science, Shanghai, China
Temporal contrast (TC) is one of the most important parameters of an ultrahigh intense laser pulse. The third-order autocorrelator or cross correlator has been widely used in the past decades to characterize the TC of an ultraintense laser pulse. A novel and simple single-shot fourth-order autocorrelator (FOAC) to characterize the TC with higher time resolution and better pulse contrast fidelity in comparison to third-order correlators is proposed. The single-shot fourth-order autocorrelation consists of a frequency-degenerate four-wave mixing process and a sum-frequency mixing process. The proof-of-principle experiments show that a dynamic range of ～1011 compared with the noise level, a time resolution of ～160 fs, and a time window of 65 ps can successfully be obtained using the single-shot FOAC, which is to-date the highest dynamic range with simultaneously high time resolution for single-shot TC measurement. Furthermore, the TC of a laser pulse from a petawatt laser system is successfully measured in single shot with a dynamic range of about 2 × 1010 and simultaneously a time resolution of 160 fs.
ultrahigh intense laser single shot temporal contrast four-wave mixing fourth-order autocorrelator Advanced Photonics
2019, 1(5): 056001
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 University of Chinese Academy of Sciences, Beijing 100049, China
3 IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240, China
The linear angular dispersion of a self-diffraction (SD) pulse, from a femtosecond laser pulse cleaning device, is compensated for by the use of a single prism. More than $500~\unicode[STIX]｛x03BC｝\text｛J｝$ first-order SD pulse has a contrast of $10^｛12｝$, which is about five orders of magnitude improvement from the input fundamental pulse. The wings of the distribution away from the main pulse in $\pm 1$ ps are cleaned with a contrast improvement of about $10^｛7｝$, which verifies the pulse cleaning ability of the SD process.
angular dispersion femtosecond self-diffraction temporal contrast. High Power Laser Science and Engineering
2018, 6(2): 02000e23
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 IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240, China
3 Tongji University, Shanghai 200092, China
A geometry of transient-grating self-referenced spectral interferometry (TG-SRSI) is proposed for weak femtosecond pulse characterization. By using a reflective microscope objective (RMO), we build a compact, robust, and easy to adjust device with a higher sensitivity to pulse energy in comparison to all previous SRSI methods. A 65 nJ/～40 fs/1 kHz pulse at 800 nm is successfully characterized, which speaks to the capability of our device to characterize a weak pulse. It is expected to extend the TG-SRSI method to the characterization of femtosecond pulses from oscillators in the near future.
190.4380 Nonlinear optics, four-wave mixing 230.0040 Detectors 320.7100 Ultrafast measurements Chinese Optics Letters
2015, 13(8): 081901
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 IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240, China
The generation of multicolored sidebands with the spectrum from 377 to 970 nm in a 0.5-mm-thick N-WG280 Schott glass based on a cascaded four-wave mixing (CFWM) process is demonstrated. The experimental setup is compact and economical. A pulse with a broadened spectrum from 670 to 900 nm is generated by utilizing two 0.18-mm-thick fused silica glass plates and is used to provide two input beams for the CFWM process. The new frequency components generated from the self-phase modulation effect in the two thin glass plates contribute to the broadening of the total spectral range of the generated multicolored sidebands.
Nonlinear optics Nonlinear optics four-wave mixing four-wave mixing Ultrafast nonlinear optics Ultrafast nonlinear optics Photonics Research
2015, 3(5): 05000210
1 武汉轻工大学机械工程学院, 湖北 武汉430023
2 武汉轻工大学食品科学与工程学院, 湖北 武汉430023
3 武汉百信环保能源科技有限公司, 湖北 武汉430023
4 武汉产品质量监督检验所, 湖北 武汉430023
应用近红外光谱技术结合支持向量机回归(support vector machine regression, SVR)方法测量食用植物油脂低碳数脂肪酸(C≤14)含量。 使用SupNIR-5700近红外光谱仪采集58个样品的近红外光谱图, 通过偏最小二乘(partial least square, PLS)算法剔除奇异样品。 选择其中具有代表性的52个样品进行主成分分析(principal component analysis, PCA), 选取径向基(radial basis function, RBF)核函数建立支持向量机回归模型, 并对光谱预处理方法和参数寻优方法进行了详细的分析和讨论。 实验表明, 经过粒子群算法(particle swarm optimization, PSO)优化后模型的性能都有所提高, 泛化能力更强, 预测的准确度和稳健性更好; 其中预处理方法2经过PSO优化寻优后的参数C=2.085, γ=22.20时, 预测集和校正集相关系数(correlation coefficient, r)分别达到了0.998 0和0.925 8, 均方根误差(root mean square error, MSE)分别为0.000 4和0.014 3。 研究结果表明, 应用近红外光谱结合PSO-SVR方法进行食用植物油脂低碳数脂肪酸含量快速、 准确的预测是可行的。
近红外光谱技术 支持向量机 低碳数脂肪酸 粒子群算法 参数优化 Near infrared spectroscopy Support vector machines Low-carbon number fatty acids Particle swarm optimization Parameter optimization 光谱学与光谱分析
2013, 33(8): 2079
