基于多个圆环嵌套结构单元, 设计、加工与测试了一种对偏振无依赖以及大角度入射稳定的三波段超材料宽带带通滤波器(BPF)。仿真结果表明该滤波器存在三个通带, 中心频率分别为7.22, 10.10, 14.46 GHz, 3 dB相对带宽分别为17.5%, 20.2%和17.4%, 中心频率处透射率分别为-0.85 dB, -0.69 dB和-1.73 dB。单元结构具有旋转对称性, 使得该滤波器对电磁波偏振不敏感, 并且在入射角达到40°时, 三个波段依然维持较好的稳定性。通过监测谐振频点处的表面电流分布情况, 分析了三波段滤波的物理机理。这种带通滤波器具有多波段滤波、偏振无依赖以及大角度入射稳定等特性, 有望在多频谱成像技术、信息通信等领域发挥一定的作用。
光学器件 带通滤波器 超材料 三波段
为了提高数字全息层析技术的动态特性，提出一种三视角实时采集数字层析全息图记录系统及层析全息图的处理方法。设计并实现了包含有三束物光波、一束参考光波的三视角离轴全息干涉光路系统，形成单幅层析全息图;根据单幅层析全息图的频谱分布特点，提出了全息图中各向干涉分量的提取方法，以折射率渐变型光纤为实验样本开展了实验分析，层析重建了光纤横截面的三维折射率。实验结果验证了这种方法的正确性和有效性，研究结果可应用于活体细胞形态的实时监测。
全息 数字全息层析技术 单幅层析全息图 三维折射率层析重建 光纤 光学学报
2013, 33(s2): s209001
Author Affiliations
Abstract
1 Department of Physics, Nanjing University of Science and Technology, Nanjing 210094, China
2 Nanoscale Technology and Engineering Laboratory, Department of Mechanical Engineering, Schulich School of Engineering, University of Calgary, Calgary, Alberta, T2N 2N4, Canada
3 Tanaka Metamaterials Laboratory, RIKEN, Saitama 351-0198, Japan
A concave two-dimensional (2D) photonic crystal waveguide (PCW) with corrugated surface is theoretically used as a focusing structure. To design this structure, a genetic algorithm is combined with the finite-difference time-domain method. For PCWs with different degrees of concaveness, the power reaches about 80% at different focusing points when the morphology of the concave surface is optimized. More importantly, the focusing location is easily controlled by changing the location of the detector placed in the output field.
光子晶体波导 遗传算法 聚焦效应 130.5296 Photonic crystal waveguides 130.3120 Integrated optics devices Chinese Optics Letters
2011, 9(1): 011301
1 南京理工大学理学院, 江苏 南京 210094
2 中国电子科技集团第二十八研究所莱斯大型电子系统工程有限公司, 江苏 南京 210007
利用二维光子晶体的自准直和定向耦合效应设计了一种由一个自准直区域、耦合区和两个周期性介质波导组成分束器, 利用平面波展开法从理论上研究了耦合区的色散关系, 计算得到了耦合长度, 同时使用时域有限差分方法模拟了电磁波在其中的传输特性, 得到了稳态的电场分布, 讨论了光波从自准直区域到光子晶体波导高效耦合的技术。结果表明：在相位匹配条件下, 从自准直区域传播到耦合区域的的电磁波可以有效的分束到两个周期性介质波导中, 同时能够弯曲任意角度, 而且透射率保持在90%以上。最后, 在设计的分束器基础上提出了一种增大点源和像点之间距离的方法。
集成光学 光子晶体分束器 同向耦合 自准直
Author Affiliations
Abstract
Department of Physics, School of Sciences, China University of Mining and Technology, Xuzhou 221008
Polarization independent bends and beam splitters for transverse electric (TE) and transverse magnetic (TM) polarizations have been demonstrated in two-dimensional (2D) photonic crystals (PhCs). In virtuel of equi-frequency contour analysis and finite-difference time-domain calculations, self-collimation behaviors for TE- and TM-polarizations are achieved at the same frequency. Simulation results show a 90-degree bend with 90% efficiency and beam splitters with about 96% total efficiency for both TE- and TM-polarizations, where the light is self-guided by the self-collimation effect. Such bends and beam splitters are expected to play important roles in optical devices where polarization insensitivity is needed.
光子晶体 自准直 光折弯 分束器 250.5300 Photonic integrated circuits 120.1680 Collimation 230.1360 Beam splitters Chinese Optics Letters
2007, 5(11): 662
