摘要
提出了一种新的表面等离子体激元透镜结构,该结构通过在两个亚波长小孔的外表面放置非周期的三角形电介质光栅实现对入射光束的有效汇聚。利用时域有限差分法(FDTD)计算了该结构中的稳态电磁场分布,讨论了光栅数目对成像特性的影响,计算发现,聚焦光斑可能出现一个、二个甚至三个;探讨了光栅折射率对成像的影响,发现在一定介质范围内,随着折射率的增大,焦距也随之增大;除此之外,亚波长小孔的数目、光栅中心距离小孔的位置及中间无三角形等因素都在不同程度上对透镜的成像特性有一定影响。
A novel plasmon polariton nanolens formed by two subwavelength metal slits surrounded by surface aperiodic triangle dielectric gratings is proposed and demonstrated numerically.Using Finite-difference Time-domain（FDTD）method the steady-state electromagnetic field distribution of the structure is calculated.And the influence of imaging characteristics on the number of gratings is discussed,which shows that focused spot may be one,two or even three.By discussing the impact on refractive index of the grating imaging,we can find that in a certain medium range,the focal length increased with the refractive index increasing.In addition,the number of subwavelength slits,the relative position between grating center and slit and other factors also have some impact on the lens′ imaging characteristics.
出处
《激光与红外》
CAS
CSCD
北大核心
2011年第11期1235-1239,共5页
Laser & Infrared
基金
淮海工学院科研启动基金(No.KQ08027)
淮海工学院自然科学课题(No.KX08039)
江苏省教育厅2008年度"青蓝工程"中青年学术带头人培养对象项目资助
