Author Affiliations
Abstract
1 Key Laboratory for Laser Plasmas (MOE), Collaborative Innovation Center of IFSA, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
2 Joint Laboratory of High Power Laser and Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, China
3 Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai, China
In strong-field physics experiments with ultraintense lasers, a single-shot cross-correlator (SSCC) is essential for fast optimization of the pulse contrast and meaningful comparison with theory for each pulse shot. To simultaneously characterize an ultrashort pulse and its long pedestal, the SSCC device must have both a high resolution and a large temporal window. However, the resolution and window in all kinds of single-shot measurement contradict each other in principle. Here we propose and demonstrate a novel SSCC device with two separate measurement channels: channel-1 for the large-window pedestal measurement has a moderate resolution but a large window, while channel-2 for the ultrashort pulse measurement has a small window but a high resolution; this allows the accurate characterization of the pulse contrast in a single shot. A two-channel SSCC device with a 200-fs resolution and 114-ps window has been developed and tested for its application in ultraintense lasers at 800 nm.
pulse contrast single-shot cross-correlator ultrashort ultraintense laser High Power Laser Science and Engineering
2022, 10(6): 06000e43
四川长虹电器股份有限公司技术中心, 成都 610041
针对相关滤波器跟踪算法在目标快速运动、遮挡和表观变化时易发生跟踪漂移或者丢失的问题, 提出一种基于时间一致性和核互相关器的目标跟踪算法。该算法通过引入对图像噪声和杂波更具鲁棒性的核互相关向量, 能够更精确地预测目标的仿射变化。同时, 在学习过程中引入时间一致性约束, 以解决因核相关器时间退化导致的跟踪漂移问题。最后, 采用主灰度分量逆映射来提升跟踪器应对目标部分遮挡的能力。在公开的OTB100标准目标跟踪数据集中与提供的基准算法和其他性能更加先进的相关滤波算法进行对比, 该算法平均跟踪速度为41f/s, 相对fDSST和SAMF算法, 其跟踪精度分别提升15.6%和6.4%, 跟踪成功率分别提升33.3%和6.1%。实验结果表明, 该算法在目标快速运动、遮挡或表观变化时仍能精确地跟踪目标。
目标跟踪 核互相关器 时间一致性约束 主灰度分量逆映射 object tracking kernel cross-correlator temporal consistent constraint MGC anti-projection
Author Affiliations
Abstract
1 Key Laboratory for Laser Plasmas (Ministry of Education)
,
Collaborative Innovation Centre of IFSA (CICIFSA)
,
School of Physics and Astronomy
,
Shanghai Jiao Tong University
,
Shanghai 200240
,
China
2 Shanghai Engineering Research Center of Ultra-precision Optical Manufacturing
,
Department of Optical Science and Engineering
,
Fudan University
,
Shanghai 200433
,
China
Pulse contrast is a crucial parameter of high peak-power lasers since the prepulse noise may disturb laser–plasma interactions. Contrast measurement is thus a prerequisite to tackle the contrast challenge in high peak-power lasers. This paper presents the progress review of single-shot cross-correlator (SSCC) for real-time contrast characterization. We begin with the key technologies that enable an SSCC to simultaneously possess high dynamic range (
), large temporal window (50–70 ps) and high fidelity. We also summarize the instrumentation of SSCC prototypes and their applications on five sets of petawatt laser facilities in China. Finally, we discuss how to extend contrast measurements from time domain to spatiotemporal domain. Real-time and high-dynamic-range contrast measurements, provided by SSCC, can not only characterize various complex noises in high peak-power lasers but also guide the system optimization.
fiber array high dynamic range pulse contrast single-shot cross-correlator High Power Laser Science and Engineering
2018, 6(4): 04000e61
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 上海科技大学物质科学与技术学院, 上海 201210
提出了一种谐振腔振荡式单次脉冲信噪比测量技术,通过精确设置谐振腔长度、两谐振腔之间的光程差、高反镜的反射或透射率,可简便地实现信噪比测量中高动态范围、大时间窗口和高时间分辨率三个关键指标。同时,采用全口径光束测量,保证了测量信号的高保真度。从理论上分析了谐振腔结构的各种功能和稳定性,以及色散引起的误差影响,在谐振腔中引入楔形高反镜,避免了次脉冲噪声的产生。理论上,该种结构可以实现1010,甚至更高信噪比的测量,而且能达到百飞秒的高时间分辨率。
测量 飞秒激光 单次脉冲 信噪比测量 互相关仪 谐振腔振荡
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 上海科技大学物质科学与技术学院, 上海 201210
A measurement technique of signal noise ratio based on resonator oscillation for single-shot pulse is proposed. Through precise setting of the resonant cavity length, optical path difference between two resonant cavities, and the reflectivity or transmittance of the high reflectivity mirror, the three key indicators of high dynamic range, large time window and high temporal resolution are easily realized. Meanwhile, high fidelity of measurement signal is guaranteed using full aperture beam measurement. Theoretically, various kinds of function and stability of the resonator structure are analyzed. Influence of errors introduced by dispersion on results are also analyzed. High reflectivity mirrors with wedge-shape are introduced in the resonator cavity to avoid the noise of minor pulses. In theory, the measurement of high signal noise ratio (1010) ,even higher signal noise ratio, and high temporal resolution of hundred femtosecond can be realized in this construction.
测量 飞秒激光 单次脉冲 信噪比测量 互相关仪 谐振腔振荡 measurement femtosecond laser single-shot pulse signal noise ratio cross-correlator resonator oscillation Collection Of theses on high power laser and plasma physics
2016, 14(1): 0904001