Author Affiliations
Abstract
1 Laser Micro/Nano Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
2 Han’s Laser Technology Industry Group Co., Ltd., Shenzhen 518126, China
In this work, we used femtosecond laser double-pulse trains to produce laser-induced periodic surface structures (LIPSS) on 304 stainless steel. Surprisingly, a novel type of periodic structure was discovered, which, to the best of our knowledge, is the first in literature. We surmised that the cause for this novel LIPSS was related to the weak energy coupling of subpulses when the intrapulse delay was longer than the thermal relaxation time of stainless steel. Furthermore, we found that the fluence combination and arrival sequence of subpulses in a double-pulse train also influenced LIPSS morphology.
femtosecond laser laser-induced periodic surface structures morphology stainless steel Chinese Optics Letters
2021, 19(12): 123801
1 杭州科澜信息技术有限公司,浙江 杭州 310022
2 重庆交通大学 土木建筑学院,重庆 400074
3 桂林理工大学 测绘地理信息学院,广西 桂林 541004
BOTDA布里渊背向散射光谱数据表现为洛伦兹型曲线,对不同的单模光纤和多模光纤会生成不同的波峰个数,单模光纤中的布里渊背向散射光谱表现为单个波峰,采用非线性最小二乘法对单峰进行拟合,采用高斯-牛顿迭代法求最小二乘解。迭代运算的效率取决于初始值的精度,当误差较大时,迭代次数会增加,甚至无法收敛。采用传统法和定积分法分别获取某一初始值。实验结果表明,在满足同等精度的条件下,定积分法能降低迭代次数,对布里渊背向散射光谱的单峰拟合具有较好的效果。
光纤通信技术 布里渊背向散射 洛伦兹型曲线 高斯-牛顿迭代法 曲线拟合 optical fiber communication technology BOTDA BOTDA Brillouin back scattering Lorenz curve Gaussian-Newton method curve fitting
Author Affiliations
Abstract
A multiplexed holographic display video has been achieved by using a passive azo-dye-doped liquid crystal (LC) cell. Holograms formed in this cell can be refreshed in the order of several milliseconds. By angular multiplexing technique, dynamically multiplexed holographic videos are realized. Moreover, the reconstructed RGB images are merged into a color image, which illustrates the possibility of a color holographic three-dimensional (3D) display by holographic multiplexing of the LC cell.
090.5694 Real-time holography 090.1705 Color holography Chinese Optics Letters
2014, 12(6): 060003
Author Affiliations
Abstract
We demonstrate by finite-difference time-domain simulations that a one-dimensional (1D) photonic crystal (PC) structure between glass substrate and indium tin oxide layer can improve the light extraction efficiency of organic light-emitting diodes. The extraction efficiency depends on the emitters' positions varying laterally in a unit cell of PC. The highest efficiency is obtained when the emitters are under higher refractive index strips. Efficiency decreases when the emitters shift to lower refractive index strips. Simulations for both transverse magnetic and transverse electric modes indicate that when emitters are close to the middle of the higher refractive index strips, the guided wave transmits with less divergence and inhibited reflection because of the guiding effect of higher refractive index strips. A modified method that considers the position effects is proposed to calculate the extraction efficiency more precisely.
230.0230 Optical devices 230.7370 Waveguides 160.5298 Photonic crystals 160.4890 Organic materials 050.5298 Photonic crystals 310.2790 Guided waves Chinese Optics Letters
2013, 11(6): 062302
