Author Affiliations
Abstract
School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 201800, China
A fiber-based source that can be exploited in a stimulated emission depletion (STED) inspired nanolithography setup is presented. Such a source maintains the excitation beam pulse, generates a ring-shaped depletion beam, and automatically realizes dual-beam coaxial alignment that is critical for two beam nanolithography. The mode conversion of the depletion beam is realized by using a customized vortex fiber, which converts the Gaussian beam into a donut-shaped azimuthally polarized beam. The pulse width and repetition frequency of the excitation beam remain unchanged, and its polarization states can be controlled. According to the simulated point spread function of each beam in the focal region, the full width at half-maximum of the effective spot size in STED nanofabrication could decrease to less than 28.6 nm.
nanolithography vortex fiber direct laser writing STED controlled fabrication Chinese Optics Letters
2021, 19(7): 072201
1 中国科学技术大学光学与光学工程系, 安徽 合肥 230026
2 光电对抗测试评估技术重点实验室, 河南 洛阳 471003
利用Mach-Zehnder (M-Z)结构的尾纤型铌酸锂(LiNbO3)电光强度调制器作为主动调Q开关元件,采用974nm半导体激光器作为泵浦源,峰值吸收系数为110 dB/m的掺杂铒光纤作为增益介质,实现了1550 nm波长的全光 纤主动调Q激光器。通过电光强度调制器对腔内损耗进行了周期性调制,实现Q开关作用, 获得了稳定的调Q脉冲输出。通过改变泵浦功率和调制频率研究了脉冲宽度和峰值功率的变化 规律,调制频率在50 Hz～88 kHz内调整时可以得到稳定输出脉冲。调制频率为1 kHz时 获得最窄脉冲宽度246 ns, 峰值功率近5 W。
激光技术 主动调Q Mach-Zehnder电光调制器 多峰现象 laser techniques actively Q-switching Mach-Zehnder electro-optical modulator multi-peak phenomenon
中国矿业大学环境与测绘学院, 江苏 徐州 221116
为了满足高精度的室内位置服务需求，提出了一种利用K-means聚类改进的迭代最近点(ICP)算法来构建结构化的二维室内地图。通过对二维激光扫描仪获取的点云数据的聚类分析，将每一帧的数据进行聚类，并通过几何中心的平移对点云数据进行预配准，利用聚类及预配准的结果对点云数据进行精确配准得到全局最优解。聚类改进的ICP算法相比于传统的ICP算法，在仅使用单一的二维激光扫描仪采集的点云数据为数据源时，能获得较高精度的配准结果。实验表明，该算法具有适用性强、配准精度高等优点，有助于在单一传感器下快速、精准地构建室内地图。
测量 迭代最近点 K-means聚类 点云配准 室内地图 激光与光电子学进展
2016, 53(5): 051202
Author Affiliations
Abstract
Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei 230026, China
A nanosecond square pulse fiber laser based on the nonlinear amplifying loop mirror (NALM) is numerically analyzed by the nonlinear Schr¨odinger equation. The fiber cavity with a NALM has a tendency to provide pulse shaping effect with nonlinearity increasing in the NALM, and the nanosecond square pulse is generated by the pulse shaping effect. The numerical results show that the stable square pulse can be obtained when the parameters of the NALM are chosen appropriately. The generated square pulses have flat top and no internal structure.
光纤激光器 纳秒方波脉冲 非线性放大环镜 脉冲整形 140.3538 Lasers, pulsed 060.2320 Fiber optics amplifiers and oscillators 060.3510 Lasers, fiber 140.4050 Mode-locked lasers Chinese Optics Letters
2011, 9(9): 091405
Author Affiliations
Abstract
Institute of Photonics, Department of Physics, University of Science and Technology of China, Hefei 230026, China
We present a flat-top laser beam generation scheme using coherent beam combining of hexagonally arranged Gaussian lasers. To produce a beam with a flat-top profile, we optimize the amplitude and phase of each unit laser using the least-square method. Simulation results show that with 13 unit lasers, a beam with the flatness of less than 1% in the optimizing region can be achieved. The main lobe contains over 95% of the total power. The scheme requires no external beam shaping element and has the potential to be designed for high-power applications.
光束整形 相干合束 平顶光束 衍射光学 140.3298 Laser beam combining 140.3300 Laser beam shaping 050.1970 Diffractive optics Chinese Optics Letters
2010, 8(1): 45
