グラフェンの歪みナノ構造のプラズモニクス開拓およびそのセンシングへの応用

双纳米栅的解析模型很简单。我们模拟了双纳米脊发射的SPP波是单纳米脊发射的SPP波的干涉结果，这一点已经讨论过了。这种相位延迟是由于等离子体波沿石墨烯-空气界面传播所致。当等离子体波在脊上传播时，它必须遵循脊曲线，与平面石墨烯相比，导致额外的传播长度。该延迟可由右曲线长度与脊下直线长度之差解析计算。我们还进行了仿真（此处未显示）来证实此相位延迟，数值结果与解析结果相匹配。在右侧，从100纳米发射的SPP波经历了150纳米脊的相位延迟，然后与从150纳米脊发射的另一个SPP波发生干扰。左侧从150 nm脊发射的SPP波也有100 nm脊的相位延迟。然而，这两个阶段的延迟是不相等的。因此，两侧的干扰是不同的，导致了不对称的定向等离子体发射。给出了解析模型的左右发射幅值之比。从这张图中，我们可以选择提供等离子体发射强方向性的条件。然后我们使用条件（275 nm脊距）进行模拟。实现了定向等离子体发射。波长分类发射（同样的结构，SPP波根据波长向左或向右发射）也实现了。

The analytic model for double nanoridge is simple. We model that the SPP wave launched from double nanoridge is just interference result of SPP wave launched by each single ridge, which is already discussed. This phase delay occurs because plasmon wave travel along graphene-air interface. When the plasmon wave propagate over ridge, it must follow the ridge curve, resulting in an extra travelling length compared to that of flat graphene. This delay can be calculated analytic from the difference between right curve length and the straight line under the ridge. We also did the simulation (not shown here) to confirm this phase delay, and the numerical result match the analytic result.For the right side, the SPP wave launched from 100-nm experienced phase delay from 150-nm ridge before interferes with another SPP wave launched from 150-nm ridge. For the left side, the SPP wave launched from 150-nm ridge also got phase delay from 100-nm ridge. However, the two phase delays are not equal. Therefore, the interference on each side is different, resulting in asymmetric directional plasmon launching.The ratio of right/left launched amplitude from the analytic model was shown. From this graph, one can choose the condition which provide strong directionality of the plasmon launching. We then use the condition (275 nm ridge separation) to perform simulation. Directional plasmon launching is achieved. Wavelength-sorted launching (same structure, SPP wave goes to left or right side depending on wavelength), is also achieved.