1 宁波大学 信息科学与工程学院 红外材料及器件实验室，浙江 宁波 315211
2 浙江省光电探测材料及器件重点实验室，浙江 宁波 315211
3 宁波海洋研究院，浙江 宁波 315832
Ge-As-Se-Te（GAST）硫族化物玻璃拥有超过20 μm的超宽透射范围，是一种可应用于中红外（MIR）和远红外(FIR)波段的优良光学材料。通过熔融淬火法制备了GexAs40−xSe40Te20（x = 0、10、20、30、40 mol%）系列硫系玻璃，采用不同波长（800 nm，3 μm和4 μm）、功率和重复频率的飞秒激光辐照硫系玻璃，利用扫描电子显微镜（SEM）和拉曼光谱等手段研究了GAST的激光损伤特性。研究结果发现，GexAs40-xSe40Te20玻璃的激光诱导损伤阈值（LIDT）随着样品中Ge含量的增加而增加，在800 nm下Ge30As10Se40Te20玻璃的LIDT达到最高40.16 mJ/cm2。随着飞秒激光波长增加，系列玻璃的LIDT也逐步增加，Ge30As10Se40Te20在4 μm激光辐照下LIDT达到81.09 mJ/cm2。此外，研究结果表明样品LIDT随着激光的脉冲辐照数量和重复率的增加将逐渐减小。
硫系玻璃 飞秒激光 激光诱导损伤阈值 chalcogenide glass femtosecond lasers laser-induced damage threshold (LIDT) 红外与激光工程
2022, 51(4): 20210222
Author Affiliations
Abstract
1 National Laboratory on High Power Laser and Physics
,
Shanghai 201800
,
China
2 Key Laboratory of High Power Laser and Physics
,
Shanghai Institute of Optics and Fine Mechanics
,
Chinese Academy of Sciences
,
Shanghai 201800
,
China
3 University of Chinese Academy of Sciences
,
Beijing 100049
,
China
Polarization mode dispersion (PMD) in fibers for high-power lasers can induce significant frequency modulation to amplitude modulation (FM-to-AM) conversion. However, existing techniques are not sufficiently flexible to achieve efficient compensation for such FM-to-AM conversion. By analyzing the nonuniform transmission spectrum caused by PMD, we found that the large-scale envelope of the transmission spectrum has more serious impacts on the amount of AM. In order to suppress the PMD-induced FM-to-AM conversion, we propose a novel tunable spectral filter with multiple degrees of freedom based on a half-wave plate, a nematic liquid crystal, and an axis-rotated polarization-maintaining fiber. Peak wavelength, free spectral range (FSR), and modulation depth of the filter are decoupled and can be controlled independently, which is verified through both simulations and experiments. The filter is utilized to compensate for the PMD-induced FM-to-AM conversion in the front end of a high-power laser facility. The results indicate that, for a pulse with phase-modulation frequency of 22.82 GHz, the FM-to-AM conversion could be reduced from 18% to 3.2% within a short time and maintained below 6.5% for 3 h. The proposed filter is also promising for other applications that require flexible spectral control such as high-speed channel selection in optical communication networks.
advanced laser technology and applications design fiber laser and applications high-power laser laser facility laser facility and engineering laser systems modeling optimization High Power Laser Science and Engineering
2018, 6(4): 04000e53
1 上海大学 特种光纤与光接入网重点实验室, 上海 200444
2 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
采用单偏振光纤远程传输待测光, 结合上升沿与顶端波形分离处理的时域恢复算法, 提出一种远程精确测量激光时间功率曲线的方法, 并对高功率激光驱动器前端系统中1 053 nm脉冲光的时间功率曲线进行了远程测量实验.结果表明, 该方法有效避免了幅频调制对激光脉冲时间功率曲线测量的影响, 获得了高保真的远程传输时间波形, 引入的误差在每1 ns范围内小于0.8%, 可用于高功率激光系统的时间功率曲线远程集中测量.
光纤光学 非线性光学 信号处理 单偏振光纤 时间功率曲线 色散 幅频调制 Fiber optics Nonlinear optics Signal processing Single polarization fiber Temporal power profiles Dispersion FM-to-AM modulation
Author Affiliations
Abstract
1 National Laboratory on High Power Lasers and Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Science, Shanghai 201800, China
2 University of the Chinese Academy of Sciences, Beijing 100049, China
FM-to-AM modulation is an important effect in the front end of high-power lasers that influences the temporal profile. Various methods have been implemented in standard-fiber and polarization-maintaining (PM)-fiber front ends to suppress the FM-to-AM modulation. To analyze the modulation in the front end, a theoretical model is established and detailed simulations carried out that show that the polarizing (PZ) fiber, whose fast axis has a large loss, can successfully suppress the modulation. Moreover, the stability of the FM-to-AM modulation can be improved, which is important for the front end to obtain a stable output. To verify the model, a PZ fiber front end is constructed experimentally. The FM-to-AM modulation, without any compensation, is less than 4%, whereas that of the PM fiber front end with the same structure is nearly 20%. The stability of the FM-to-AM modulation depth is analyzed experimentally and the peak-to-peak and standard deviation (SD) are 2% and 0.38%, respectively, over 3 h. The experimental results agree with the simulation results and both prove that the PZ fiber front end can successfully suppress the FM-to-AM conversion. The PZ fiber front end is a promising alternative for improving the performance of the front end in high-power laser facilities.
Lasers frequency modulated Phase modulation Wave propagation Fusion Collection Of theses on high power laser and plasma physics
2016, 14(1): 8352
Author Affiliations
Abstract
1 National Laboratory on High Power Laser and Physics, Shanghai 201800, China
2 Key Laboratory of High Power Laser and Physics, Shanghai Institute of Optics and fine Mechanics, Chinese Academy of Science, Shanghai 201800, China
3 University of Chinese Academy of Sciences, Beijing 100049, China
A fiber-based，high precision long-term stable time synchronization system for multi-channel laser pulses is presented，using fiber pulse stacker combined with high-speed optical-electrical conversion and electronics processing technology. This scheme is used to synchronize two individual lasers including a mode-lock laser and a time shaping pulse laser system. The relative timing jitter between two laser pulses achieved with this system is 970 fs (rms) in five minutes and 3.5 ps (rms) in five hours. The synchronization system is low cost and can work at over several tens of MHz repetition rate.
ICF OPCPA time synchronization long-term stable Collection Of theses on high power laser and plasma physics
2016, 14(1): 10019
1 东南大学自动化学院， 江苏 南京 210096
2 复杂工程系统测量与控制教育部重点实验室， 江苏 南京 210096
通过利用光栅投影三维测量技术进行微小物体的三维重构,提出了基于一般成像模型的标定方法，利用标定板围绕固定轴转动的不同姿态进行标定并进行优化。所提出的标定算法既解决了一般成像模型变量多的问题，又不需要借助精密位移装置，简化了整个标定过程。与此同时，利用自卷积盲去模糊的方法解决远心镜头景深小带来的离焦，提高了摄像机的标定精度。标定和三维重构实验验证了该方法的可行性和准确性。在23.7 mm×17.78 mm相机视场范围下系统测量精度达到了6 μm。
测量 一般成像模型 光栅投影 标定 自卷积
