Wang Yujia, Sun Chengwei, Gong Qihuang, Chen Jianjun
Opt Lett. 2017 Oct 15;42(20):4235-4238. doi: 10.1364/OL.42.004235.
By drawing an analogy with the conventional photonic crystals, the plasmonic bandgaps have mainly employed the periodic metallic structures, named as plasmonic crystals. However, the sizes of the plasmonic crystals are much larger than the wavelengths, and the large sizes considerably decrease the density of the photonic integration circuits. Here, based on the coupled-resonator effect, the plasmonic bandgaps are experimentally realized in the subwavelength waveguide-resonator structure, which considerably decreases the structure size to subwavelength scales. An analytic model and the phase analysis are established to explain this phenomenon. Both the experiment and simulation show that the plasmonic bandgap structure has large fabrication tolerances (>20%). Instead of the periodic metallic structures in the bulky plasmonic crystals, the utilization of the subwavelength plasmonic waveguide-resonator structure not only significantly shrinks the bandgap structure to be about λ/13, but also expands the physics of the plasmonic bandgaps. The subwavelength dimension, together with the waveguide configuration and robust realization, makes the bandgap structure easy to be highly integrated on chips.
通过与传统光子晶体进行类比，表面等离激元带隙主要采用了被称为表面等离激元晶体的周期性金属结构。然而，表面等离激元晶体的尺寸远大于波长，而大尺寸会显著降低光子集成电路的密度。在此，基于耦合谐振器效应，在亚波长波导 - 谐振器结构中通过实验实现了表面等离激元带隙，这将结构尺寸大幅减小至亚波长尺度。建立了一个解析模型和相位分析来解释这一现象。实验和模拟均表明，表面等离激元带隙结构具有较大的制造容差（>20%）。利用亚波长表面等离激元波导 - 谐振器结构，而非庞大的表面等离激元晶体中的周期性金属结构，不仅显著将带隙结构缩小至约λ/13，还拓展了表面等离激元带隙的物理内涵。亚波长尺寸，连同波导配置和可靠的实现方式，使得带隙结构易于在芯片上实现高度集成。
