石墨烯表面涡旋光束的局域动力学特性分析  

Local Dynamical Characteristics of Vortex Beams on the Graphene Surface

作　　者：马万琦 崔志伟[1] MA Wanqi;CUI Zhiwei(School of Physics,Xidian University,Xi′an 710071,China)

机构地区：[1]西安电子科技大学物理学院,西安710071

出　　处：《光子学报》2023年第2期270-278,共9页Acta Photonica Sinica

基　　金：广东省自然科学基金(No.2022A1515011138);中央高校基本科研业务费(No.QTZX22042)。

摘　　要：结合角谱展开方法和矢量势方法,推导了拉盖尔高斯涡旋光束在石墨烯表面反射后的电磁场分量显式表达式。分析了光束的入射角和拓扑荷数,以及石墨烯-衬底系统的费米能量和磁场对涡旋光束在石墨烯表面反射后局域动力学特性的影响。数值结果表明,石墨烯表面反射涡旋光束的能量、动量、自旋/轨道角动量密度分布随着光束入射角和拓扑荷数的变化发生显著变化。同时,改变石墨烯-衬底系统的费米能量和磁场可以有效调节反射涡旋光束的局域动力学特性。为基于涡旋光束局域动力学特性对石墨烯的表征以及基于石墨烯对涡旋光束的调控奠定了理论基础。Graphene,a one-atom-thick layer of carbon atoms arranged in a hexagonal honeycomb lattice,has attracted intensive attention and extensive investigation because of its striking electronic and optical properties.Especially,the reflection coefficients of graphene are determined by the fine structure constant and intrinsic parameters,which can be tuned by altering the Fermi level.Such interesting feature makes graphene a good candidate for tuning the optical properties of structured light.On the other hand,structured light beams with vortex phase have become a research hotspot in optics and optoelectronics due to their unique physical properties and novel physical effects,as well as various promising potential applications.It is well known that the complex amplitude of a vortex beam comprises a phaseexp(ilφ),wherelis an integer often called the topological charge andφis the azimuthal angle.A common example of the vortex beams is the Laguerre-Gaussian(LG)beams.As a special type of electromagnetic wave,the LG vortex beams can carry energy,momentum,and angular momentum,which can be classified into Spin Angular Momentum(SAM)and Orbital Angular Momentum(OAM).As well known,energy,momentum,SAM,and OAM are the main dynamical characteristics of light and play a crucial role in understanding the light-matter interactions.There has been a recent study on the dynamical characteristics of vortex beams reflected from an air-glass interface.However,to the best of our knowledge,the local dynamical characteristics of vortex beams reflected from a graphene-substrate interface have not been reported.Compared to the conventional air-glass interface,graphene-substrate interface may reveal many other important and interesting features of the vortex beams upon reflection.Meanwhile,the dynamical characteristics of reflected vortex beams are of great importance in understanding the optical properties of graphene.In this work,we investigate the dynamical characteristics of the vortex beams impinging on graphene-substrate surfaces.Firstly,th

关 键 词：涡旋光束 石墨烯 能量 动量 自旋角动量 轨道角动量 

分 类 号：O436[机械工程—光学工程]