Author Affiliations
Abstract
1 College of Electronics and Information Engineering, Sichuan University, Chengdu 610064, China
2 Fiber Optics Research Centre, School of Information and Communication Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China
In this Letter, we experimentally investigate fast temporal intensity dynamics and statistical properties of the cladding-pumped Er/Yb co-doped random Rayleigh feedback fiber laser (EYRFL) for the first time, to the best of our knowledge. By using the optical spectral filtering method, strong and fast intensity fluctuations with the generation of extreme events are revealed at the output of EYRFL. The statistics of the intensity fluctuations strongly depends on the wavelength of the filtered radiation, and the intensity probability density function (PDF) with a heavy tail is observed in the far wings of the spectrum. We also find that the PDF of the intensity in the central part of the spectrum deviates from the exponential distribution and has the dependence on the laser operating regimes, which indicates some correlations among different frequency components exist in the EYRFL radiation and may play an important role in the random lasing spectrum stabilization process.
random fiber laser temporal dynamics Rayleigh scattering Chinese Optics Letters
2021, 19(2): 021402
河北大学 物理科学与技术学院, 河北 保定 071002
为了丰富介质阻挡放电系统中斑图的多样性, 利用双水电极介质阻挡放电装置, 在空气和氩气按一定比例混合的气体中(氩气含量χ=25%), 发现了带晕蜂窝六边形斑图。通过观察用普通相机拍摄的斑图照片, 可以发现斑图是由中心点、晕和蜂窝框架构成, 且中心点位于晕的中心, 中心点和晕嵌套在蜂窝框架的中心。采用带有3个通道的高速照相机对斑图进行分脉冲瞬态拍摄, 结果显示带晕蜂窝六边形斑图的3套子结构在外加电压的半周期内, 总是按照晕-蜂窝框架-中心点这样的顺序放电。运用光电倍增管对这3套子结构进行研究, 发现晕的放电在时间和空间上具有局部选择性。利用发射光谱法, 根据氮分子第二正带系(C3Πu→B3Πg)谱线计算了中心点、晕和蜂窝框架的分子振动温度, 结果显示: 中心点的分子振动温度为2 632 K, 晕的分子振动温度为2 679 K, 蜂窝框架的分子振动温度为2 720 K。本文利用壁电荷理论解释带晕蜂窝六边形斑图的形成机制和时空结构。
介质阻挡放电系统 带晕蜂窝六边形斑图 时空动力学 壁电荷 DBD honeycomb superlattice pattern with hole spatio-temporal dynamics wall charges
Physics Department, Blackett Laboratory, Imperial College, Blackett Laboratory London SW7 2BZ
继对整体耦合激光列阵的讨论,本文介绍作者最近对局部耦合激光列阵的研究结果.文中采用连续的近似方法,推导出描述耦合激光列阵的连续模型.正如数字计算结果所表明,耦合激光系统是另外一个很典型的“光学流体”系统.本文还对如何设计耦合激光系统,使之具有高功率、单模输出并保持良好的光束特性,进行了定性的讨论.对波导式耦合的本征不稳定性,运用孤子理论进行了初步的分析,进而讨论了耦合激光列阵中的孤子波现象及其应用.
激光列阵 时空动力学 G-L方程
