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

双纳米脊的解析模型很简单。我们的模型认为，从双纳米脊发射的SPP波只是每个单脊发射的SPP波的干涉结果，这一点已经讨论过了。这种位相延迟是由于等离子体波沿石墨烯-空气界面传播造成的。当等离子体波在脊线上传播时，它必须沿着脊线曲线传播，这导致了比平坦的石墨烯多出一个行进长度。这一延迟可以根据右曲线长度与山脊下直线之间的差解析计算。我们还进行了模拟(这里没有显示)来确认这种相位延迟，数值结果与解析结果一致。对于右侧，从100 nm发射的SPP波经历了从150 nm脊处的相位延迟，然后与从150 nm脊处发射的另一个SPP波进行了干涉。对于左侧，从150 nm脊处发射的SPP波从100 nm脊处也得到了相位延迟。然而，这两个阶段的延迟并不相等。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度比。从这张图中，人们可以选择提供等离子体激元发射的强方向性的条件。然后，我们使用该条件(275 nm脊线间距)进行模拟。实现了定向等离子激元发射。还实现了波长分选发射(相同结构，SPP波根据波长向左或向右)。

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.