Zhang Xiang, Li Zhi, Chen Jianjun, Yue Song, Gong Qihuang
State Key Laboratory for Mesoscopic Physics and Department of Physics, Peking University, Beijing 100871, China.
Opt Express. 2013 Jun 17;21(12):14548-54. doi: 10.1364/OE.21.014548.
An asymmetric T-shape nanoslit in a metal film is proposed to act as an efficient dichroic surface-plasmon-polariton (SPP) splitter, which is composed of a single nanoslit in immediate contacting with two nanogrooves with different widths. Simulations show that, due to the interferences of SPPs in the upper part of the asymmetric T-shape nanoslit, the generated SPPs propagating to the left and right directions on the front metal surface can be manipulated nearly independently by altering the right and left groove widths, respectively. Based on such effects, a dichroic SPP splitter is demonstrated and the splitting wavelengths can easily be adjusted. High splitting ratios of 31:1 and 1:12 at splitting wavelengths of 680 nm and 884 nm are numerically presented with a device's lateral dimension of only 1200 nm. Further experimental results match the simulations well.
提出了一种金属薄膜中的非对称T形纳米狭缝，用作高效的二向色性表面等离子体激元（SPP）分离器，它由单个纳米狭缝与两个不同宽度的纳米凹槽直接接触组成。模拟表明，由于非对称T形纳米狭缝上部的SPP干涉，通过分别改变左右凹槽宽度，可以几乎独立地控制在前金属表面上向左和向右传播的生成SPP。基于这些效应，展示了一种二向色性SPP分离器，并且可以轻松调整分裂波长。在仅1200 nm的器件横向尺寸下，数值给出了在680 nm和884 nm分裂波长处分别为31:1和1:12的高分裂比。进一步的实验结果与模拟结果非常吻合。
