1 哈尔滨工业大学光电子信息科学与技术系，黑龙江 哈尔滨 150080
2 哈尔滨工业大学可调谐激光技术国家级重点实验室，黑龙江 哈尔滨 150080
毛细管放电极紫外激光是一种小型化的纳秒极紫外激光光源。相比自由电子激光和同步辐射等短波长光源，该光源具有运行成本低、单脉冲能量高和机时充足等显著优势。随着毛细管放电极紫外激光光源的发展，其输出已提高至深度饱和区，并且实现了重复频率输出、多波长输出等多样化输出方式。小型化的灵活性和优质的输出参数使其逐渐成为进行极紫外激光应用研究的理想光源。本文介绍了自1994年毛细管放电极紫外激光成功输出至今，该光源在微纳结构加工、物质成分检测、生物科学以及高分辨成像等领域的前沿应用。在微纳加工方面，极短的波长和极小的能量衰减深度使得该光源能够在纳米量程内进行材料的刻蚀。同时，较长的激光脉宽增加了极紫外激光诱导自组织微纳结构的可能性。在物质成分检测方面，极紫外激光的高能量光子能够以单光子电离材料表面，结合飞行时间质谱仪测量纳米尺度范围内的材料成分，便可实现超高分辨的物质组成分布检测。在生物科学领域，极紫外激光能够实现对微观生物样本的三维成分扫描，获得更多的表征信息。在高分辨成像方面，基于极紫外激光的短波长和良好的相干性，以Gabor同轴等方法进行高分辨成像能达到接近照明光水平的成像分辨率。已有的应用成果表明，毛细管放电极紫外激光是探索微观世界、制造微观结构的有力工具。在人类对短波长光源需求日益增长的今天，毛细管放电极紫外激光将有更多的机会展现它的应用价值和优势。
激光技术 极紫外激光 毛细管放电 激光微纳加工 高分辨成像 质谱检测
Author Affiliations
Abstract
National Key Laboratory of Science and Technology on Tunable Laser, Harbin Institute of Technology, Harbin 150080, China
In this paper, the influence of the delay time between the pre-pulse and the main pulse on the double-pass amplified 46.9 nm laser was studied for the first time, to the best of our knowledge, by using a high-precision polished SiC slice as a rear mirror. The temporal and spatial characteristics of the output laser were measured separately to investigate the effect of the delay time on the laser characteristics. The energy of the double-pass amplified laser was between 510 µJ and 890 µJ. In addition, a theoretical model of double-pass amplification was established to analyze the effect of the delay time on the double-pass amplified 46.9 nm laser.
double-pass amplification delay time 46.9 nm laser capillary discharge Chinese Optics Letters
2023, 21(5): 053401
1 哈尔滨工业大学可调谐激光技术国家级重点实验室, 黑龙江 哈尔滨 150080
2 哈尔滨工业大学空间光学工程研究中心, 黑龙江 哈尔滨 150080
探究了在毛细管内充入气压比为8∶1的Ar-He混合气体条件下,初始气压对46.9 nm激光输出特性的影响。通过测量Ar-He混合气体产生46.9 nm激光的气压范围和每个气压下对应的激光强度与光斑形态信息,总结出激光输出特性与初始气压的关系。然后,从等离子体柱的角度分析了混合气体初始气压对激光光斑的影响,得到了混合气体初始气压导致46.9 nm激光输出特性发生变化的原因。以上对激光特性的研究对于提高激光幅值和改变光斑形状有益。
光学学报
2022, 42(11): 1134022
Author Affiliations
Abstract
National Key Laboratory of Tunable Laser Technology, Institute of Optoelectronics, Department of Electronics Science and Technology, Harbin Institute of Technology, Harbin 150080, China
In this Letter, we firstly, to the best of our knowledge, demonstrated the influence of pre-pulse current and delay time on the intensity of a discharge pumped Ne-like Ar soft X-ray laser operating at 46.9 nm by employing an alumina capillary having an inner diameter of 4.8 mm. Specifically, the delay time was changed from 8 to 520 μs in small intervals. The pre-discharge current was increased from 25 A to 250 A through small steps, while keeping the main discharge current constant. Usually, a small pre-discharge current is applied to an Ar-filled capillary to attain a plasma column having sufficient pre-ionization before the injection of the main current. The pre-discharge current of 140 A was declared the best current to obtain lasing with a 4.8 mm diameter capillary. The laser spots were captured at best time delays for the pre-discharge currents of 25, 45, 80, 140, and 250 A, which support the experimental results. We observed that by applying the pre-discharge current of 140 A, the laser spot exhibits small divergence, higher symmetry, and uniformity, which is clear evidence of strong amplification. The laser spot obtained at 140 A is cylindrically symmetric and has a better structure than those reported by all other groups in the literature. Hence, the laser spot indicates that the laser beam is highly focusable and beneficial for the applications of the 46.9 nm laser. Results of this Letter might open a new way to enhance applications of a 46.9 nm capillary discharge soft X-ray laser.
Z-pinch pre-discharge kink instabilities beam divergence Chinese Optics Letters
2020, 18(11): 111403
哈尔滨工业大学可调谐激光技术国家级重点实验室, 黑龙江 哈尔滨 150080
为了研究类镍氪32.8 nm激光输出所需的等离子体状态，利用Cowan程序计算了类镍氪32.8 nm激光系统的有关原子参数。根据能级参数，建立并求解了准稳态近似下的有关能级速率方程，计算获得了激光上、下能级的相对粒子数密度和相对增益系数随电子温度和电子密度的变化规律，并分析了3d94p、3d94d和3d94f组态的能级对激光产生的影响。通过理论计算得到实现类镍氪32.8 nm激光输出所需的最佳等离子体状态。最佳电子温度约为75 eV，最佳电子密度约为1018 cm-3。计算结果为未来开展毛细管放电抽运类镍氪32.8 nm激光实验提供了理论依据。
原子与分子物理学 类镍氪 软X射线激光 相对增益系数 电子密度 电子温度
