Subwavelength beam focusing via multiple-metal slits arranged along a triangle surface
Subwavelength beam focusing via multiple-metal slits arranged along a triangle surface
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通过沿三角形表面排列的多个金属狭缝进行亚波长光束聚焦
DOI：
10.1016/j.optcom.2015.06.024
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发表时间：
2015
影响因子：
2.4
通讯作者：
Hou Xun
中科院分区：
文献类型：
--
作者：
Jia Sen;Wu Yiming;Si Jinhai;Chen Feng;Hou Xun
提出了一种紧凑的等离子体激元结构，通过沿着三角形或菱形表面排列的金属狭缝阵列实现亚波长光束聚焦。入射光以表面等离子体激元（SPPs）的形式穿过金属狭缝，然后散射到辐射场中。来自具有不同深度和宽度的单个狭缝的辐射场的相长干涉引起光束聚焦。所提出的等离子体透镜的优点是具有小得多的横向尺寸和宽的工作波长范围。这对于实现密集集成的光子电路具有重要意义。时域有限差分法（FDTD）的方法来验证所提出的设计。仿真结果表明，焦斑超过了衍射极限。
A compact plasmonic structure is proposed to actualize the subwavelength beam focusing, through a metal slit array arranged along a triangular or trapezium surface profile. The incident light passes through the metal slits in the form of surface plasmon polaritons (SPPs) and then scattered into radiation fields. The constructive interference of radiation fields from individual slits with different depths and widths gives rise to beam focusing. The advantages of the proposed plasmonic lens are having a much smaller lateral dimension and broad working wavelength range. This is of importance for realizing densely integrated photonic circuits. The finite-difference time-domain (FDTD) method is employed to verify the proposed design. The simulation results indicate that the focal spot is beyond the diffraction limit.