1 深圳技术大学 新材料与新能源学院，广东 深圳 518118
2 深圳盛方科技有限公司，广东 深圳 518173
为了获得稳定性更好、能量更大的准分子激光输出脉冲，对合束方式提高输出脉冲能量稳定性的可行性进行了理论推导、模拟实验以及合束实验研究。从理论推导得知，当激光输出脉冲能量符合正态分布时，多台激光器合束可以降低输出能量相对标准差。对三台输出脉冲能量分布特性符合正态分布的准分子激光器进行合束模拟实验研究，每台输出脉冲能量平均值约为153 mJ，脉冲能量相对标准差约为1%。两台准分子激光器合束时得到输出脉冲能量平均值为305 mJ、能量相对标准差为0.7%的准分子激光脉冲。三台准分子激光器合束时可以得到输出能量平均值为458 mJ、能量相对标准差为0.6%的准分子激光脉冲。使用两台准分子激光器进行三次实际合束实验，其中两台准分子激光器三次合束分别输出能量平均值约为355、350、330 mJ，相对标准差为1.3%、1.2%、1.4%的激光脉冲；三次合束后分别得到能量平均值为687、694、646 mJ，相对标准差为0.86%、0.79%、0.83%的激光脉冲。模拟实验以及合束实验都表明，合束后的能量相对标准差均小于单台能量相对标准差，即合束提高准分子输出脉冲的稳定性。因此，当单台准分子激光输出脉冲能量符合正态分布且平均能量相当时，多台合束可以有效提高激光输出脉冲的能量稳定性。
准分子激光 脉冲能量 稳定性 相对标准差 excimer laser pulse energy stability relative standard deviation 红外与激光工程
2024, 53(1): 20230309
Shuailin Liu 1,2,3Bin Zhang 1,2,3,*Yuanzhuang Bu 1,2,3Desheng Zhao 1,2,3[ ... ]Jing Hou 1,2,3,*
Author Affiliations
Abstract
1 College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha, China
2 Nanhu Laser Laboratory, National University of Defense Technology, Changsha, China
3 Hunan Provincial Key Laboratory of High Energy Laser Technology, Changsha, China
We report a Yb-doped all-fiber laser system generating burst-mode pulses with high energy and high peak power at a GHz intra-burst repetition rate. To acquire the uniform burst envelope, a double-pre-compensation structure with an arbitrary waveform laser diode driver and an acoustic optical modulator is utilized for the first time. The synchronous pumping is utilized for the system to reduce the burst repetition rate to 100 Hz and suppress the amplified spontaneous emission effect. By adjusting the gain of every stage, uniform envelopes with different output energies can be easily obtained. The intra-burst repetition rate can be tuned from 0.5 to 10 GHz actively modulated by an electro-optic modulator. Optimized by timing control of eight channels of analog signal and amplified by seven stages of Yb-doped fiber amplifier, the pulse energy achieves 13.3 mJ at 0.5 ns intra-burst pulse duration, and the maximum peak power reaches approximately 3.6 MW at 48 ps intra-burst pulse duration. To the best of our knowledge, for reported burst-mode all-fiber lasers, this is a record for output energy and peak power with nanosecond-level burst duration, and the widest tuning range of the intra-burst repetition rate. In particular, this flexibly tunable burst-mode laser system can be directly applied to generate high-power frequency-tunable microwaves.
burst-mode laser fiber laser high peak power high pulse energy High Power Laser Science and Engineering
2023, 11(6): 06000e81
1 苏州大学光电科学与工程学院，江苏 苏州 215006
2 江苏省先进光学制造技术重点实验室，江苏 苏州 215006
3 江苏省苏州大学现代光学技术教育部重点实验室，江苏 苏州 215006
4 奥徒（上海）激光技术有限公司，江苏 苏州 215123
利用飞秒激光脉冲开展了零热膨胀系数Li2O-Al2O3-SiO2（LAS）透明微晶玻璃的非光学接触式焊接研究，分析了不同能量飞秒激光焊接LAS透明微晶玻璃的焊缝形貌和剪切强度，并对焊接后LAS透明微晶玻璃的透过率进行了测量。在激光脉冲宽度为300 fs、波长为1030 nm、单脉冲能量为3.0 μJ时，焊接后LAS透明微晶玻璃的剪切强度高达23.51 MPa，光学透过率相对于原始LAS透明微晶玻璃下降了5%。随着单脉冲能量的增加，LAS透明微晶玻璃的光学透过率发生不同程度的下降，改性区域逐渐远离焦点，向激光源方向移动，使得分界面处的焊缝宽度先增大至10.7 μm而后逐渐减小。X射线衍射分析结果表明，在该激光参数下实现了LAS透明微晶玻璃焊接而未产生新的晶相。
激光技术 飞秒激光 透明微晶玻璃 玻璃焊接 单脉冲能量 非光学接触 中国激光
2023, 50(16): 1602104
强激光与粒子束
2023, 35(6): 065005
Desheng Zhao 1,2,3Bin Zhang 1,2,3,*Xiran Zhu 1,2,3Shuailin Liu 1,2,3[ ... ]Jing Hou 1,2,3,*
Author Affiliations
Abstract
1 College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha, China
2 Nanhu Laser Laboratory, National University of Defense Technology, Changsha, China
3 Hunan Provincial Key Laboratory of High Energy Laser Technology, Changsha, China
We propose a 2.1 μm high-energy dissipative soliton resonant (DSR) fiber laser system based on a mode-locked seed laser and dual-stage amplifiers. In the seed laser, the nonlinear amplifying loop mirror technique is employed to realize mode-locking. The utilization of an in-band pump scheme and long gain fiber enables effectively exciting 2.1 μm pulses. A section of ultra-high numerical aperture fiber (UHNAF) with normal dispersion and high nonlinearity and an output coupler with a large coupling ratio are used to achieve a high-energy DSR system. By optimizing the UHNAF length to 55 m, a 2103.7 nm, 88.1 nJ DSR laser with a 3-dB spectral bandwidth of 0.48 nm and a pulse width of 17.1 ns is obtained under a proper intracavity polarization state and pump power. The output power and conversion efficiency are 0.233 W and 4.57%, respectively, both an order of magnitude higher than those of previously reported holmium-doped DSR seed lasers. Thanks to the high output power and nanosecond pulse width of the seed laser, the average power of the DSR laser is linearly scaled up to 50.4 W via a dual-stage master oscillator power amplifier system. The 3-dB spectral bandwidth broadens slightly to 0.52 nm, and no distortion occurs in the amplified pulse waveform. The corresponding pulse energy reaches 19.1 μJ, which is the highest pulse energy in a holmium-doped mode-locked fiber laser system to the best of our knowledge. Such a 2.1 μm, high-energy DSR laser with relatively wide pulse width has prospective applications in mid-infrared nonlinear frequency conversion.
High Power Laser Science and Engineering
2023, 11(1): 01000e12
红外与激光工程
2022, 51(6): 20220055
西安工业大学 光电工程学院，陕西 西安 710021
高脉冲能量和窄脉冲宽度的激光放大器可以应用在诸多领域，例如激光加工、激光医疗美容和激光雷达。种子源激光器与行波放大结构相结合的主振荡功率放大（MOPA）技术，既能保证输出的脉冲激光相关特性（如脉宽和重复频率等）与种子源特性一致，又能实现激光输出能量的放大。因此MOPA技术成为激光放大器工程应用中的主要技术。本课题针对医疗美容对亚纳秒级大能量激光放大器的需求，研制了一台基于亚纳秒微片固体激光器的激光放大器。首先，采用亚纳秒被动调Q微片固体激光器作为种子源。种子源激光器在重复频率为10 Hz，脉冲宽度为487.3 ps时输出能量为190 μJ的1064 nm种子光。然后，利用自制的两个氙灯泵浦Nd: YAG模块作为主放大器对亚纳秒激光脉冲能量进行放大，对放大过程自激振荡产生的能量实现了抑制，有效地提高了放大过程中的能量转换效率。最终，得到了波长1064 nm和532 nm可切换输出，在重复频率为10 Hz时，获得了脉冲宽度496.4 ps，脉冲能量561 mJ@1064 nm，330 mJ@532 nm，能量稳定性2%且光斑均匀的亚纳秒激光输出。
亚纳秒 高能量 氙灯泵浦 波长可切换 放大器 sub-nanosecond high pulse energy xenon lamp pumping wavelength switchable amplifier 红外与激光工程
2022, 51(4): 20210200
1 北京工业大学材料与制造学部，北京市激光应用技术工程技术研究中心，北京 100124
2 北京工业大学跨尺度激光成型制造技术教育部重点实验室，北京 100124
3 北京工业大学激光工程研究院，北京 100124
4 Edgewave公司，Würselen 52146，德国
本文报道了利用自制低损耗、无节点反谐振空芯光纤传输高功率1064 nm皮秒脉冲激光的研究。光纤包层由7根平均壁厚为700 nm的细玻璃管组成，纤芯直径为42 μm，外径为175 μm。选择脉冲宽度为15 ps且重复频率可调谐的高功率激光器作为实验光源。使用不同长度的光纤进行了传输测试，测试结果表明：当输入单脉冲能量为403 μJ、平均功率为40.3 W、峰值功率为26.8 MW的激光时，最高可实现370 μJ的高能量激光输出，传输效率高达91.8%。分析了超短脉冲经过不同长度光纤后时域和频域的变化情况，结果表明：当光纤长度为1 m时，脉冲保持无畸变传输，光谱发生轻微变形；当光纤长度增长至3.3 m时，由于非线性效应的影响，脉冲宽度展宽至26 ps，光谱展宽至70 nm。本研究表明无节点反谐振空芯光纤有望在超短脉冲激光的传输应用领域发挥重要作用。
激光光学 超短脉冲传输 无节点反谐振空芯光纤 峰值功率 单脉冲能量 非线性效应
红外与激光工程
2021, 50(8): 20210349
