1 中国科学院长春光学精密机械与物理研究所 发光学及应用国家重点实验室，吉林 长春 130033
2 中国科学院大学，北京 100049
提高上转换发光效率是促进上转换发光材料实际应用的关键。在NaErF4@NaYF4体系中，惰性NaYF4壳层可以抑制高组分Er3+掺杂下的发光浓度猝灭，其上转换发光主要来源于Er3+⁃Er3+的能量传递上转换。本文利用共沉淀法制备了Er3+和Yb3+分区掺杂的NaErF4@NaYbF4@NaYF4核壳结构的纳米颗粒，通过包覆惰性壳层研究Er3+⁃Yb3+⁃Er3+之间的能量传递和反向能量传递过程。由于808 nm波长只能激发Er3+而不能激发Yb3+，因此在808 nm波长激发下，Er3+在惰性壳层的保护作用下将激发态能量传递给Yb3+，随后通过反向能量传递回Er3+，使得Er3+的上转换发光增强。实验结果发现，当中间层Yb3+掺杂浓度为100%时，绿色和红色上转换发光最大增强倍数为24.9和9.79。
稀土纳米材料 上转换发光 反向能量传递 β-NaErF4 rare earth nanoparticles upconversion luminescence back energy transfer β-NaErF4
1 武汉科技大学信息科学与工程学院, 湖北 武汉 430081
2 华中科技大学光学与电子信息学院, 湖北 武汉 430074
提出一种具有巨旋光性和负折射特性的双频带手征性超表面结构,该手征性超表面由中间介质层和双层共轭卍字形周期排列而成;通过研究面电流密度分布,解释了巨旋光性和负折射率产生的原因;研究了手征性超表面单元结构的连续圆金属贴片半径和介质层厚度对该结构旋光性和负折射特性的影响。数值模拟结果表明:该结构在0.1~2 THz频率范围内有4个谐振频点,在谐振频点附近,平均折射率均为负值,实部幅值最大为-3.7;该结构在谐振频点附近显示了巨旋光性以及双频带的左旋圆偏振波和右旋圆偏振波负折射特性,最大偏振旋转角达到了122°,右旋圆偏振波折射率实部幅值可达-12.74。
材料 手征性超表面 双频带 圆二向色性 旋光性 负折射率
Author Affiliations
Abstract
1 State Key Laboratory of Information Photonics and Optical Communication, Beijing University of Posts and Telecommunications, Beijing 100876, China
2 University of Texas at Dallas, Texas 75080, USA
In this Letter, we propose two crosstalk-aware routing, core, and spectrum assignment (CA-RCSA) algorithms for spatial division multiplexing enabled elastic optical networks (SDM-EONs) with multi-core fibers. First, the RCSA problem is modeled, and then a metric, i.e., CA spectrum compactness (CASC), is designed to measure the spectrum status in SDM-EONs. Based on CASC, we propose two CA-RCSA algorithms, the first-fit (FF) CASC algorithm and the random-fit (RF) CASC algorithm. Simulation results show that our proposed algorithms can achieve better performance than the baseline algorithm in terms of blocking probability and spectrum utilization, with FF-CASC providing the best performance.
060.1155 All-optical networks 060.4250 Networks 060.4251 Networks, assignment and routing algorithms Chinese Optics Letters
2016, 14(10): 100604
Author Affiliations
Abstract
Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications, Ministry of Education, Beijing 100876, China
The combination of fast polarization scrambler (FPS) and forward error correction (FEC) is one of the methods to mitigate the polarization mode dispersion (PMD) in high-speed optical fiber communication systems. The effect of the different distribution patterns of FPS on PMD mitigation with FEC is investigated. A comparison of the bit error rates (BERs) between two cases where the distributed FPS is absent and present along the fiber is carried out by simulation. A novel representation called the "ring chart" to assess the performance of different distribution patterns intuitively is proposed. The results show that the distribution pattern is an impact factor for this PMD mitigation scheme.
偏振模色散缓解 前向纠错 快速扰偏器 分布模式 060.0060 Fiber optics and optical communications 230.0230 Optical devices 250.0250 Optoelectronics Chinese Optics Letters
2011, 9(7): 070604
1 中国科学院,研究生院,北京,110039
2 中国科学院,沈阳自动化所,机器人学重点实验室,辽宁,沈阳,110016
3 香港中文大学,微纳米技术中心,香港 Shatin N.T
随着微机电系统(MEMS)设计日趋成熟,度量问题越来越成为微系统技术中的热点.使用改进的拉普拉斯求和方法(SML)和深度估计法来测量热度驱动微夹持器末端的弯曲程度.实验中,使用了10幅在42℃时微夹持器的水下工作图像来验证这种光学聚焦方法,结果证明使用光学聚焦方法可以测量出作为驱动器反馈输入的末端弯曲大小,实现对驱动器运动的精确控制.
微机电系统 SML算法 深度估计 Micro electrical mechanism systems Sum-modified-laplacian algorithm Depth estimation
