基于单层二硫化钼的高品质因子、高品质因数的四波段完美吸收器  

A four-band perfect absorber based on high quality factor and high figure of merit of monolayer molybdenum disulfide

作　　者：蒋黎英 易颖婷 易早 杨华[3] 李治友 苏炬 周自刚[1] 陈喜芳 易有根[2] Jiang Li-Ying;Yi Ying-Ting;Yi Zao;Yang Hua;Li Zhi-You;Su Ju;Zhou Zi-Gang;Chen Xi-Fang;Yi You-Gen(School of Science,Southwest University of Science and Technology,Mianyang 621010,China;School of Physics and Electronics,Central South University,Changsha 410083,China3School of Science,Lanzhou University of Technology,Lanzhou 730050,China;School of Science,Lanzhou University of Technology,Lanzhou 730050,China)

机构地区：[1]西南科技大学理学院,绵阳621010 [2]中南大学物理与电子学院,长沙410083 [3]兰州理工大学理学院,兰州730050

出　　处：《物理学报》2021年第12期342-353,共12页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:1187522);四川省科学技术厅科研基金(批准号:2020YJ0137,2020YFG0467);西南科技大学理学院创新基金(批准号:LX2020010)资助的课题。

摘　　要：采用时域有限差分方法从理论和数值上提出了一种基于临界耦合和导模共振的单层二硫化钼的四波段完美吸收器,通过阻抗匹配和耦合模理论可以更好地分析其物理机理.单层二硫化钼被放置在二氧化硅与具有周期性长方体空气槽结构的二维聚甲基丙烯酸甲酯层中间.利用导向共振的临界耦合原理得到了单层二硫化钼的高效光吸收,即在共振波长(λ_(1)=510.0 nm,λ_(2)=518.8 nm,λ_(3)=565.9 nm,λ_(4)=600.3 nm)获得了4个共振完美吸收峰,吸收率分别为99.03%,98.10%,97.30%和95.41%,同时平均吸收率在可见光光谱范围高达97.46%,是裸单层二硫化钼的12倍以上.从模拟结果来看,调节结构的几何参数可以来控制单层二硫化钼的共振波长的范围,这对提高单层二硫化钼的吸收强度和选择性具有重要的现实意义.利用临界耦合来增强光-二氧化硅相互作用的新思想也可以应用于其他原子级薄材料.同时,本文也讨论了吸收器的传感性能,发现传感器的最高品质因子、灵敏度与品质因数最高分别为1294.1,155.1 nm/RIU和436.这些结果表明,所设计的结构可能为改善二维过渡金属二元化合物中的光-物质相互作用开辟有前景的技术,并在波长选择性光致发光和光电探测中有着极好的应用前景.Transition-metal dichalcogenides with exceptional electrical and optical properties have emerged as a new platform for atomic-scale optoelectronic devices.However,the poor optical absorption resists their potential applications.In this paper,monolayer molybdenum disulfide four-band perfect absorber based on critical coupling and guided mode resonance is proposed theoretically and numerically by the finite difference time domain method.Meanwhile,the physical mechanism can be better analyzed through impedance matching and coupled mode theory.Monolayer molybdenum disulfide is placed between the silicon dioxide and a twodimensional polymethyl methacrylate layer with a periodic square-shaped air groove structure.The three form a sandwich-like stacked structure similar to a rectangle.The bottom of the absorber uses a silver layer as the back reflection layer.Using the critical coupling principle of guided resonance,the high-efficiency light absorption of the monolayer molybdenum disulfide is obtained,that is,four perfect resonances are obtained at the resonance wavelengths(λ_(1)=510.0 nm,λ_(2)=518.8 nm,λ_(3)=565.9 nm,andλ_(4)=600.3 nm),the absorption rates are 99.03%,98.10%,97.30%,and 95.41%,and the average absorption rate is as high as 97.46%in the visible light spectrum range,which is over 12 times more than that of a bare monolayer MoS_(2).The simulation results show that the adjusting of the geometric parameters of the structure can control the range of the resonance wavelength of the monolayer molybdenum disulfide,the system experiences three states,i.e.under-coupling,critical coupling,and over-coupling because of the leakage rate of resonance,thereby exhibiting advantageous tunability of operating wavelength in monolayer MoS_(2),which has important practical significance for improving the absorption intensity and selectivity of the monolayer molybdenum disulfide.The novel idea of using critical coupling to enhance the light-MoS_(2) interaction can also be adopted in other atomically thin materials.At the same

关 键 词：临界耦合 二硫化钼 完美吸收 可见光光谱范围 

分 类 号：TQ136.12[化学工程—无机化工]