Author Affiliations
Abstract
1 School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
2 Zhangjiang Laboratory, Shanghai 201204, China
3 Shanghai Key Laboratory of Modern Optical System, University of Shanghai for Science and Technology, Shanghai 200093, China
The chiral feature of an optical field can be evaluated by the parameter of -factor enhancement, which is helpful to enhance chiroptic signals from a chiral dipole. In this work, the superchiral spot has been theoretically proposed in metal-insulator-metal waveguides. The -factor enhancement of the superchiral spot can be enhanced by 67-fold more than that of circularly polarized light, and the spot is confined in the deep wavelength scale along each spatial dimension. Moreover, the position of the superchiral spot can be tuned by manipulating the incident field. The tunable superchiral spot may find applications in chiral imaging and sensing.
circular dichroism superchiral spot radially polarized beam metal-insulator-metal waveguide Chinese Optics Letters
2023, 21(1): 013601
Author Affiliations
Abstract
1 School of Physics and Optoelectronic Engineering, Guangdong University of Technology, Guangzhou 510006, China
2 Guangdong Provincial Key Laboratory of Information Photonics Technology, Guangdong University of Technology, Guangzhou 510006, China
3 School of Information Engineering, Guangdong University of Technology, Guangzhou 510006, China
In this paper, a Bragg reflector is proposed by placing periodic metallic gratings in the center of a metal-insulator-metal (MIM) waveguide. According to the effective refractive index modulation caused by different waveguide widths in a period, a reflection channel with a large bandwidth is firstly achieved. Besides, the Mach-Zehnder interference (MZI) effect arises by shifting the gratings away from the waveguide center. Owing to different optical paths with unequal indices on both sides of the grating, a narrow MZI band gap will be obtained. It is interesting to find out that the Bragg reflector and Mach-Zehnder interferometer are immune to each other, and their wavelengths can be manipulated by the period and the grating length, respectively. Additionally, we can obtain three MZI channels and one Bragg reflection channel by integrating three different gratings into a large period. The performances are investigated by finite-difference time-domain (FDTD) simulations. In the index range of 1.33 – 1.36, the maximum sensitivity for the structure is as high as 1 500 nm/RIU, and it is believed that this proposed structure can find widely applications in the chip-scale optical communication and sensing areas.
Bragg reflector metal-insulator-metal Mach-Zehnder interference effective refractive index modulation Photonic Sensors
2022, 12(3): 220303
兰州大学信息科学与工程学院光电子与电磁信息研究所，甘肃 兰州 730000
基于表面等离子激元构造了一种边界耦合模式的金属-绝缘体-金属结构滤波器，该滤波器由两个斜对称矩形环谐振腔及波导管所组成，采用有限元法对该滤波器进行仿真计算和分析，得到它的磁场分布图和透射谱线图。结果表明，该滤波器在通带部分的透射率最高可达0.969，阻带部分的透射率最低接近为0，同时还具有通带与阻带较宽、透射谱线平滑的特点。调节结构参数可使得透射谱线图发生红移或蓝移的现象，设置特定的结构参数可以实现在保持第一通信窗口通过的状态下，对第二、三通信窗口的通断进行选择性控制的功能，因此，该滤波器可作为一种带通/带阻滤波器，在高密度集成电路和光纤通信中有着非常重要的应用。另外通过结构的改进并加入电光材料DAST实现了一种电光开关的功能。
集成光学 表面等离子激元 金属-绝缘体-金属结构滤波器 斜对称双矩形环 透射谱线图 带通/带阻滤波器 电光开关 有限元法 激光与光电子学进展
2022, 59(19): 1913001
研究同侧、异侧和反对称双loop-stub(LS)谐振腔侧边耦合波导结构中的多重类电磁诱导透明效应,并利用有限元方法分别对这三种结构的光学透射特性进行数值模拟。结果表明,这三种结构的透射谱、磁场分布和色散强烈地依赖结构参数。着重讨论双LS谐振腔相邻两个stub腔的距离或两个水平分支的距离对透射特性的影响。随着距离的减小,两个LS腔之间的耦合增强,出现多个透射峰和透射谷(即阻带),多重类电磁诱导透明效应显著。此外,讨论了同侧双LS腔波导结构相邻两个stub腔的距离为零时,竖直分支宽度、水平分支宽度、总水平分支长度等参数对透射谱的影响。侧边耦合金属纳米波导结构在未来的集成光学有潜在的应用价值,如滤波器、传感器和慢光装置等。
光学器件 表面等离激元 电磁诱导透明 金属-介质-金属波导 有限元法 光学学报
2022, 42(10): 1023002
1 桂林电子科技大学 广西无线宽带通信与信号处理重点实验室, 广西 桂林 541004
2 深圳大学 光电子器件与系统教育部重点实验室, 广东 深圳 518060
针对现阶段表面等离子体激元(SPP)传感器存在灵敏度低、结构制造复杂等问题，提出了一种由金属-绝缘体-金属波导和嵌入银纳米棒的谐振腔构成的高灵敏度、可调谐的SPP传感器。采用时域有限差分法对所设计传感器的光传输特性及传感特性进行了理论研究。仿真结果表明：当谐振腔引入或者不引入银纳米棒时，传输谱在500~3500 nm波长范围会呈现4个或者2个谐振峰；该结构的折射率灵敏度高达2116.72 nm/RIU,品质因数为27.503；通过对谐振腔填充乙醇，该结构可实现对环境温度的测量，温度灵敏度可达0.982 nm/℃。
等离子体激元 金属-绝缘体-金属波导 谐振腔 传感器 灵敏度 plasmon polariton metal-insulator-metal waveguide resonant cavity sensor sensitivity
Author Affiliations
Abstract
1 Institute of Advanced Magnetic Materials, College of Materials & Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, China
2 College of Electronics and Information, Hangzhou Dianzi University, Hangzhou 310018, China
3 Department of Materials Science and Engineering, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China
Nanogap plasmonic structures with strong coupling between separated components have different responses to orthogonal-polarized light, giving rise to giant optical chirality. Here, we proposed a three-dimensional (3D) nanostructure that consists of two vertically and twistedly aligned nanogaps, showing the hybridized charge distribution within 3D structures. It is discovered that the structure twisted by 60° exhibits plasmonic coupling behavior with/without gap modes for different circular-polarized plane waves, showing giant chiral response of 60% at the wavelength of 1550 nm. By controlling the disk radius and the insulator layer, the circular dichroism signal can be further tuned between 1538 and 1626 nm.
metal-insulator-metal structure nanogaps gap mode twisted stacking charge distribution chiral response Chinese Optics Letters
2021, 19(1): 013601
Author Affiliations
Abstract
1 Department of Technical Cybernetic, Samara National Research University, Samara 443086, Russia
2 Institute of RAS-Branch of the FSRC “Crystallography and Photonics”, RAS, 151 Molodogvardeiskaya, Samara 443001, Russia
We propose a highly refractive index sensor based on plasmonic Bow Tie configuration. The sensitivity of the resonator design is enhanced by incorporating a nanowall (NW) in a modified Bow Tie design where sharp tips of V-junction are flattened. This approach provides high confinement of electric field distribution of surface plasmon polariton (SPP) mode in the narrow region of the cavity. Consequently, the effective refractive index (neff) of the mode increases and is highly responsive to the ambient medium. The sensitivity analysis of the SPP mode is calculated for six resonator schemes. The results suggest that the NW embedded cavity offers the highest mode sensitivity due to the large shift of effective index when exposed to a slight change in the medium refractive index. Moreover, the device sensitivity of the proposed design is approximated at 2300 nm/RIU which is much higher than the sensitivity of the standard Bow Tie configuration.
Bow Tie configuration plasmonic sensor metal-insulator-metal waveguide refractive index sensor Photonic Sensors
2020, 10(3): 223
Author Affiliations
Abstract
1 School of Architecture & Urban Planning, Lanzhou Jiaotong University, Lanzhou 730070, China
2 School of Science, Lanzhou University of Technology, Lanzhou 730050, China
In this paper, we describe a new method to improve fast-light transmission, which uses cascades. We design a simple plasmonic device that enables plasmonic-induced absorption (PIA). It consists mainly of two parallel rectangular cavities. The numerical results simulated by using the finite element method (FEM) confirm its function. The corresponding group delay-time can reach –0.146 ps for the PIA window. Based on this result, we propose a cascade device, with the dual-rectangular cavity system as building block, to improve fast-light transmission even more. The results indicate that the cascade scheme can increase the group delay-time to –0.456 ps, which means the fast-light feature is substantially enhanced compared with the non-cascading approach. The effect of the distance between two cascade resonators and other structural parameters is also investigated. Finally, we use this design concept to build a refractive-index sensor with a sensitivity of 701 nm/RIU.
Plasmonic-induced absorption fast light metal-insulator-metal waveguide finite element method Photonic Sensors
2020, 10(2): 162
1 西北师范大学物理与电子工程学院, 甘肃 兰州 730070
2 甘肃省智能信息技术与应用工程研究中心, 甘肃 兰州 730070
基于口径耦合的方法提出了金属-绝缘体-金属电压可调滤波器,该滤波器由两个非对称的矩形环腔和一个矩形波导管组成,其中非对称的矩形环腔内填充有机电光材料4-二甲氨基-N-甲基-4-甲苯磺酸盐(DAST)。利用有限元法仿真分析了非对称矩形环腔波导结构的透射光谱、谐振波长分布和磁场强度分布。结果表明,该滤波器的传输频谱比较平滑,通带带宽和阻带带宽较宽,通带的透射率高达97%,阻带的透射率低至0.01%。该滤波器的特性不仅可以通过改变结构参数进行调整,还可以通过施加控制电压进行调节,可调节性较高,且优化结构后阻带带宽更宽,可在集成光学中应用。
表面等离子激元 金属-绝缘体-金属滤波器 有限元法 矩形环腔 电光材料4-二甲氨基-N-甲基-甲苯磺酸盐(DAST) 口径耦合 光学学报
2020, 40(14): 1423001
