1 西北工业大学物理科学与技术学院光场调控与信息感知工业和信息化部重点实验室，陕西省光信息技术重点实验室，陕西 西安 710129
2 兰州理工大学理学院，甘肃 兰州 730050
本文研究了金属光栅表面等离激元与单层二硫化钨激子的耦合共振特性。利用时域有限差分法模拟了一维金光栅/单层二硫化钨混合结构的光谱响应及电场强度分布。结果表明，金光栅表面等离激元与单层二硫化钨激子耦合可产生光谱劈裂。当改变金光栅的结构参数时，混合结构的反射光谱出现了明显的反交叉现象。采用时域耦合模理论拟合了混合结构不同参数时的反射光谱，拟合结果与数值模拟符合较好。金光栅表面等离激元与单层二硫化钨激子的耦合作用满足强耦合判据。耦合振荡器模型分析结果表明，当金光栅周期为400 nm、宽度为300 nm时，混合结构强耦合光谱的拉比劈裂为54.6 meV，其与时域耦合模理论结果一致。该工作将为表面等离激元与激子强耦合作用的深入研究与器件开发开辟新途径。
表面等离激元 一维金光栅 二硫化钨 激子 强耦合
Author Affiliations
Abstract
MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions, Key Laboratory of Light-Field Manipulation and Information Acquisition, Ministry of Industry and Information Technology, and Shaanxi Key Laboratory of Optical Information Technology, School of Physical Science and Technology, Northwestern Polytechnical University, Xi’an 710129, China
We present the perfect light absorption of monolayer molybdenum disulfide () in a dielectric multilayer system with two different Bragg mirrors. The results show that the strong absorption of visible light in monolayer is attributed to the formation of optical Tamm states (OTSs) between two Bragg mirrors. The absorption spectrum is dependent on the layer thickness of Bragg mirrors, incident angle of light, and the period numbers of Bragg mirrors. Especially, the nearly perfect light absorption (99.4%) of monolayer can be achieved by choosing proper period numbers, which is well analyzed by the temporal coupled-mode theory.
optical Tamm states molybdenum disulfide light absorption Chinese Optics Letters
2021, 19(10): 103801
西北工业大学理学院超常条件材料物理与化学教育部重点实验室与陕西省光信息技术重点实验室, 陕西 西安 710072
提出了一种增强石墨烯光吸收率的布拉格光栅/石墨烯/金属薄膜光学结构。运用传输矩阵和时域有限差分法研究了其光传输特性,发现布拉格光栅与金属薄膜之间形成的塔姆等离激元局域场可有效增强光与石墨烯的相互作用,单层石墨烯的近红外光吸收率约增大了36倍。探讨了布拉格光栅的周期、石墨烯位置、入射角度、布拉格光栅层厚度及石墨烯化学势与石墨烯光吸收的关系。研究结果表明,上述物理参数的变化可有效调控石墨烯的光吸收波长及效率。研究结果为高性能石墨烯探测器等新型光电子器件的实现提供了新的途径。
薄膜 光学薄膜 石墨烯 塔姆等离激元 光吸收
Author Affiliations
Abstract
MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions, and Shaanxi Key Laboratory of Optical Information Technology, School of Science, Northwestern Polytechnical University, Xi’an 710072, China
We demonstrate an all-fiber Q-switched cylindrical vector laser based on a black phosphorus saturable absorber and a transverse mode converter. The saturable absorber is prepared by incorporating the polyvinyl alcohol with anti-oxidized black phosphorus nanosheets exfoliated in aqueous poly(dimethyldiallyl ammonium chloride) solution. The mode converter is composed of a tapered two-mode fiber and a single-mode fiber, and it can excite switchable azimuthally and radially polarized beams by modulating the input polarization. By enhancing the pump power from 64.68 to 174.82 mW, the repetition rate of the Q-switched azimuthally/radially polarized laser enlarges from 16.72/19.25 to 30.71/37.82 kHz.
140.3540 Lasers, Q-switched 190.4400 Nonlinear optics, materials Chinese Optics Letters
2019, 17(2): 020004
