外尔半金属调制的范德瓦耳斯声子极化激元色散性质  

Dispersion properties of van der Waals phonon polaritons modulated by Weyl semimetals

作　　者：顾梓恒 臧强[1,2] 郑改革 Gu Zi-Heng;Zang Qiang;Zheng Gai-Ge(School of Automation,Nanjing University of Information Science and Technology,Nanjing 210044,China;Jiangsu Collaborative Innovation Center on Atmospheric Environment and Equipment Technology,Nanjing 210044,China;School of Physics and Optoelectronic Engineering,Nanjing University of Information Science and Technology,Nanjing 210044,China)

机构地区：[1]南京信息工程大学自动化学院,南京210044 [2]江苏省大气环境与装备技术协同创新中心,南京210044 [3]南京信息工程大学物理与光电工程学院,南京210044

出　　处：《物理学报》2023年第19期226-233,共8页Acta Physica Sinica

基　　金：江苏省自然科学基金(批准号:BK20191396)资助的课题。

摘　　要：极性电介质支持的表面声子极化激元(surface phonon polaritons,SPhP)在红外波段增强光与物质相互作用过程中引起了广泛的关注,然而存在光场操控有限、调制波段限定在剩余射线带区域的问题.提出了一种由双轴范德瓦耳斯材料(a-MoO_(3))和外尔半金属组成的异质结构,用来研究各向异性SPhP的主动可调谐性.在横磁波入射条件下,通过4×4传递矩阵法准确地求解异质系统中的反射系数以及场分布,描述各向异性SPhP的色散性质.研究结果表明:模式杂化和色散操控可以通过方位角度及a-MoO_(3)的厚度大小实现.更重要的是外尔半金属中费米能级的大小能够启用动态色散曲线调节,而费米能级依赖于外界温度的变化.因此研究有助于进一步优化和设计基于范德瓦耳斯材料的可控光电器件,在红外热辐射和生物传感等方面具有较好的应用前景.Surface phonon polaritons(SPhP)as an alternative constituent for mid-infrared(MIR)nanophotonic applications have attracted extensive attention and they maybe solve the intrinsic loss problem of plasmonics.SPhP arise in polar dielectrics due to IR-active phonon resonances,leading to negative permittivity within the Reststrahlen band.Although SPhP have great potential in enhancing the interaction between light and matter in the infrared region,it is still limited to enhance optical fields and fixed resonance band because of the existing Reststrahlen band.Moreover,active manipulating of phonon polaritons in MIR range remains elusive.The significant research progress of natural van der Waals(vdW)crystal and heterostructures have been made,which are characterized by an anisotropic polaritonic response,leading to elliptical,hyperbolic,or biaxial polaritonic dispersions.Among these structures,SPhP with hyperbolicity in a-MoO_(3)are of particular interest,due to not only the strong field confinement,low losses,and long lifetimes,but also the natural in-plane anisotropic dispersion.A heterostructure composed of a biaxial vdW material(a-MoO_(3))and a Weyl semimetal(WSM)is proposed to study the active tunability of anisotropic SPhP.The control of polaritons can show more degrees of freedom,which has not yet been addressed.Under the incident condition of transverse magnetic incident wave,the reflection coefficient and field distribution in the heterogeneous system are accurately solved by the 4×4 transfer matrix method,and the dispersion properties of anisotropic SPhP are described in detail.Variation of dispersion spectrum with azimuthal angle and a-MoO_(3)thickness is presented.The research results indicate that mode hybridization and dispersion manipulation can be realized by controlling the azimuth angle and the thickness of a-MoO_(3).More importantly,the Fermi level of WSM enable the adjustment of dynamic dispersion curve,which depends on the change of external temperature.Isofrequency curves of hybridized SPhP at diff

关 键 词：外尔半金属 表面声子极化激元 各向异性 色散关系 

分 类 号：O469[理学—凝聚态物理]