1 西安科技大学理学院，陕西 西安 710054
2 西安科技大学安全工程与科学学院，陕西 西安 710054
连续域束缚态（BIC）已被广泛用于设计具有高品质因数（Q值）谐振的超材料中。通过在一个周期单元中设置两对高折射率裂环谐振器（SRR），设计了一种太赫兹全介质超材料。基于超晶格模式的对称性保护原理，通过改变其中两个SRR之间的距离，获得了可观测的准BIC（QBIC）模式。通过调节不对称度可以调制Q值，并且QBIC的Q值与结构的不对称度之间呈现出二次反比的关系。感应电场和磁场的空间分布以及感应电流的多极展开都表明了谐振是由电四极子的激发引起的。所提出的超材料具有较窄的谐振线宽，其灵敏度和FOM（figure of merit）分别为254.8 GHz/RIU和509.6，可以作为高灵敏度的折射率传感器。
材料 连续域束缚态 太赫兹 全介质超材料 电四极子 折射率传感 光学学报
2023, 43(23): 2316002
1 CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, China
2 University of Chinese Academy of Sciences, Beijing 100049, China
In recent years, two-dimensional (2D) materials have attracted extensive interests due to the large exciton binding energy different from bulk materials. Many peculiar properties have been discovered that have far-reaching perspectives in the next generation of optoelectronic devices. In this review, we introduce the forms of exciton existence in 2D materials and several promising 2D materials with good applications at first. Then, we summarize relevant contemporary tools for probing exciton dynamics and methods of regulating 2D exciton transport, for instance, electrical regulation, stress/surface wave regulation and moiré potential regulation, etc. Finally, we conclude the general development of regulation in 2D materials and propose several possible opportunities of application prospect.In recent years, two-dimensional (2D) materials have attracted extensive interests due to the large exciton binding energy different from bulk materials. Many peculiar properties have been discovered that have far-reaching perspectives in the next generation of optoelectronic devices. In this review, we introduce the forms of exciton existence in 2D materials and several promising 2D materials with good applications at first. Then, we summarize relevant contemporary tools for probing exciton dynamics and methods of regulating 2D exciton transport, for instance, electrical regulation, stress/surface wave regulation and moiré potential regulation, etc. Finally, we conclude the general development of regulation in 2D materials and propose several possible opportunities of application prospect.
materials exciton diffusion transition metal dichalcogenide van deer Waals heterostructure trion moiré exciton
为了实现太赫兹波的保偏波导传输，设计了一种含有纤芯缺陷孔和椭圆形包层空气孔的高双折射微结构光纤。通过在包层空气孔中选择性地填充太赫兹近零介电常量（epsilon-near-zero, ENZ）材料，引入了几何结构和材料分布的双重不对称性，破坏了2个偏振基模的简并以获得高双折射特性。应用有限元方法研究了光纤的双折射、损耗和色散等传输特性随结构参数的变化规律。在0.5 THz~2 THz的宽频段范围内获得了大于0.01的高双折射。x和y偏振基模的损耗在0.8 THz附近具有最小值，分别为0.903 dB·cm−1和0.851 dB·cm−1。纤芯缺陷孔可以有效调节色散特性，y偏振基模在1 THz~1.8 THz范围内具有 (0±0.054) ps·THz−1·cm−1近零平坦色散特性。光纤的传输特性对ENZ材料的折射率变化不敏感。研究结论为研制太赫兹保偏光纤提供了理论参考。
Author Affiliations
Abstract
1 Key Laboratory for Quantum Optics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
2 University of Chinese Academy of Sciences, Beijing 100049, China
3 Wuhan Optics Valley Aerospace Sanjiang Laser Industrial Technology Research Institute Co., Ltd., Wuhan 430075, China
4 Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
The influence of the sparsity of random speckle illumination on traditional ghost imaging (GI) and GI via sparsity constraint (GISC) in a noise environment is investigated. The experiments demonstrate that both GI and GISC obtain their best imaging quality when the sparsity of random speckle illumination is 0.5, which is also explained by some parameters such as detection of the signal to noise ratio and mutual coherence of the measurement matrix.
ghost imaging sparsity speckle illumination noise environment Chinese Optics Letters
2021, 19(4): 041103
Author Affiliations
Abstract
1 Key Laboratory of Quantum Optics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
2 Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
3 Wuhan Optics Valley Aerospace Sanjiang Laser Industrial Technology Research Institute Co., Ltd., Wuhan 430075, China
4 Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
We propose a color ghost imaging approach where the object is illuminated by three-color non-orthogonal random patterns. The object’s reflection/transmission information is received by only one single-pixel detector, and both the sparsity constraint and non-local self-similarity of the object are utilized in the image reconstruction process. Numerical simulation results demonstrate that the imaging quality can be obviously enhanced by ghost imaging via sparsity constraint and non-local self-similarity (GISCNL), compared with the reconstruction methods where only the object’s sparsity is used. Factors affecting the quality of GISCNL, such as the measurement number and the detection signal-to-noise ratio, are also studied.
ghost imaging image reconstruction non-local self-similarity Chinese Optics Letters
2021, 19(2): 021102
本文提出了一种利用信息论研究光学成像系统的新方法。通过改进傅里叶变换，光强函数被分解成一系列非负谐波的线性组合。物的归一化谐波系数集合可看作信源，像的归一化谐波系数集合可看作信宿。利用成像积分方程的特征值可得到光学信道矩阵。进而通过计算平均互信息和信道容量来评估光学系统的信息传递能力。
信息论 信息熵 平均互信息 信道容量 改进傅里叶变换 information theory information entropy average mutual information information channel capacity improved Fourier transform
