1 南开大学现代光学研究所, 天津 300350
3 广东华快光子科技有限公司, 广东 中山 528437
从啁啾脉冲放大技术到精密光谱学光频梳,从超分辨荧光显微术到飞秒化学,这些(分别获得2018、2005、2014、1998年度诺贝尔物理奖和化学奖)举世瞩目的科学成就,无不彰显了超短脉冲激光对人类科技创新和认知力的深远影响。对超短脉冲激光的特点、表征方法、产生与放大途径等一些重要基础知识进行回顾,对用于先进制造业中的超短脉冲激光系统的基本光学结构、各种主要技术指标及实际工业加工应用中一些关键激光参数的合理选择予以介绍。最后还呈现一幅在多年教学实践基础上绘制的“超快激光光学”学习路线图,并以此作为对超短脉冲激光相关科学技术知识框架的一种整体描绘。
激光光学 超短脉冲激光 超快激光 超快激光工业应用 激光加工 中国激光
2019, 46(12): 1200001
Author Affiliations
Abstract
1 State Key Laboratory of Advanced Optical Communication Systems and Networks, School of Electronics Engineering and Computer Science, Peking University, Beijing 100871, China
2 National Research Center for Optoelectronic Engineering, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100871, China
3 Ultrafast Laser Laboratory, Key Laboratory of Opto-electronic Information Technical Science of Ministry of Education, School of Precision Instrument and Opto-electronics Engineering, Tianjin University, Tianjin 300072, China
4 Huakuai Photonic Technologies Inc., Zhongshan 528400, China
We demonstrate a strain compensated long lifetime semiconductor saturable absorber mirror (SESAM) with a high modulation depth for fiber lasers. The SESAM was measured to have a damage threshold of 9.5 mJ/cm2, a modulation depth of 11.5%, a saturation fluence of 39.3 μJ/cm2, and an inversed saturable absorption coefficient of 630 mJ/cm2. The SESAM has been applied to a linear cavity mode-locked Yb-doped fiber laser, which has been working for more than a year without damage of the SESAM.
140.4050 Mode-locked lasers 140.3510 Lasers, fiber 160.6000 Semiconductor materials Chinese Optics Letters
2019, 17(7): 071404
南开大学现代光学研究所光学信息技术科学教育部重点实验室, 天津 300071
本文采用共线和非共线两种大动态范围扫描三阶相关技术测量飞秒激光脉冲，并对其测量结果及其特征进行了理论和实验分析。实验发现，共线式扫描三阶相关方法由于存在基频光在空气中通过三倍频过程直接产生三次谐波的现象，导致实际能够测量的动态范围下降；而非共线式扫描三阶相关技术虽然对脉冲强度具有较高的动态测量范围，但非共线夹角和光斑的大小对测量脉冲宽度有很大的影响。理论计算和实验结果表明，非共线情况下，入射到和频晶体上的光束夹角和光斑直径越大，测量得到的脉冲宽度也越大。共线和非共线两种方式均不影响对次脉冲位置的判断，但由于非共线式三阶相关测量得到的脉冲宽度增加，主脉冲附近的小脉冲结构或者距离较近的两个脉冲将会难以分辨。
超快光学 扫描式三阶相关仪 非共线和频 脉冲宽度 脉冲对比度
1 安徽大学 计算机智能与信号处理教育部重点实验室,安徽 合肥 230039
2 安徽大学 电子科学与技术学院,安徽 合肥 230039
为了可靠实现点模式匹配,提出了一种基于谱相关性的概率松弛匹配算法。先根据待匹配点集的形状上下文计算初始匹配概率,然后由待匹配点集构造亲近矩阵并进行奇异值分解,将得到的谱的相关性作为初始支持度。最后利用概率松弛迭代方法实现两个点集之间的匹配。实验结果表明该算法匹配精度较高。
机器视觉 匹配 谱相关性 形状上下文 概率松弛 奇异值分解
Author Affiliations
Abstract
School of Science, Hebei University of Technology, Tianjin 300130, China
The pulse profile influence of excitation light on the two-photon absorption coefficient \beta is theoretically and numerically studied. Based on Gaussian spatial and temporal laser, we obtain an expansion formula of energy transmission. As compared with a plain beam and a pulse beam that is rectangular in time but Gaussian in space, the relative deviations of \beta turn out to be about 214% and 47%, respectively. These differences indicate that a smaller \beta may be obtained than the real one in usual nonlinear transmission. Our result suggests that by taking real pulse profile into account, a more exact \beta can be derived in energy transmission measurement.
非线性能量透过率 双光子吸收 高斯脉冲 偏差 分子吸收截面 190.4710 Optical nonlinearities in organic materials 020.4180 Multiphoton processes 140.3538 Lasers, pulsed 160.4330 Nonlinear optical materials Chinese Optics Letters
2010, 8(1): 93
