摘要
在中红外至太赫兹的电磁场长波谱段,二维范德瓦耳斯晶体石墨烯和a-MoO_(3)能够分别支持等离极化激元和双曲声子极化激元,实现对长波电磁场的纳米尺度聚焦和调控。不同类型极化激元之间的杂化可以进一步丰富极化激元物理特性,为纳米尺度下的电磁场调控带来更多维度。为此开展了a-MoO_(3)薄片和单层石墨烯异质叠层结构声子极化激元-等离极化激元杂化研究。在理论上通过求解二维光波导麦克斯韦波动方程,分析了a-MoO_(3)/石墨烯异质叠层结构中声子极化激元-等离极化激元杂化激元波导模式的传播特性,计算了波导模式的色散关系,揭示了a-MoO_(3)/石墨烯异质叠层结构特有的电磁场传输机制。在实验上通过干法转移制备了a-MoO_(3)/单层石墨烯异质叠层结构,并采用散射式扫描近场光学显微镜对该异质结构的杂化极化激元特性进行了三维空间纳米光学成像表征,验证了理论结果。研究结果为计算范德瓦耳斯二维晶体叠层结构的杂化极化激元特性提供了定量模型,为研究二维晶体中不同类型的极化激元之间的相互作用及其机制提供了理论和实验参考。
Objective Two-dimensional(2D)van der Waals(vdW)crystals like graphene and a-MoO_(3)can support polaritons in the spectral range from terahertz to mid-/far-infrared regime,enabling nanoscale confining,focusing,and controlling of the electromagnetic fields.The hybridization between different polaritons can further enrich the properties of polaritons and bring more degrees of freedom for the regulation of electromagnetic fields at the nanoscale.In this paper,we studied the hybridization of plasmon polaritons and phonon polaritons in a heterostructure composed of an a-MoO_(3)vdW thin lamina stacking onto a monolayer graphene.An analytical waveguide model was developed to calculate the polariton propagation characteristics in the vdW heterostructure.The dispersion contours,dispersion relations,and localized electromagnetic field distributions of the hybridized polariton waveguide modes were derived.The theoretical results were then verified by real-space optical nano-imaging and numerical simulations.Our study can provide a quantitative model for the calculation of the hybridized polariton waveguide modes in vdW heterostructures,which can help further exploring the interactions between different types of polaritons in 2D vdW crystals.Methods In our theoretical model,the vdW heterostructure is treated as a 2D infinite waveguide supported onto SiO_(2) substrate,which consists of a monolayer graphene of 0.5-nm thickness and an a-MoO_(3)lamina of 115-nm thickness(Fig.1).The dielectric functions of the graphene and a-MoO_(3)are described using the Drude model and Lorentz model,respectively.Because in a-MoO_(3)the polaritons can approximately be treated as transverse magnetic(TM)mode,the electromagnetic modes and the associated dispersion relations of the heterostructure can then be obtained by solving the Maxwell’s equations upon the continuities of the electric and magnetic fields at interfaces.Monolayer graphene was grown by the chemical vapor deposition(CVD)method.Microfabrication technique combining electron beam lit
作者
孙凤升
郑泽波
黄悟朝
许宁生
王锡描
王天武
陈焕君
邓少芝
Sun Fengsheng;Zheng Zebo;Huang Wuchao;Xu Ningsheng;Wang Ximiao;Wang Tianwu;Chen Huanjun;Deng Shaozhi(State Key Laboratory of Optoelectronic Materials and Technologies,Guangdong Province Key Laboratory of Display Material and Technology,School of Electronics and Information Technology,Sun Yat-sen University,Guangzhou 510275,Guangdong,China;Frontier Institute of Chip and System,Fudan University,Shanghai 200433,China;GBA Branch of Aerospace Information Research Institute,Chinese Academy of Sciences,Guangzhou 510700,Guangdong,China;Shenzhen JL Computational Science and Applied Research Institute,Shenzhen 518131,Guangdong,China)
出处
《中国激光》
EI
CAS
CSCD
北大核心
2023年第1期176-187,共12页
Chinese Journal of Lasers
基金
国家重点研发计划(2019YFA0210200,2019YFA0210203)
国家自然科学基金(91963205,11904420)
广东省自然科学基金(2020A1515011329)
教育部长江学者奖励计划青年项目。
