Ultrafast shifted-core coaxial nano-emitter.
Ultrafast shifted-core coaxial nano-emitter.
复制标题
超快移芯同轴纳米发射器。
作者：
Xi Li;Q. Gu
我们提出了一种利用移芯同轴纳米腔的超快纳米级光源，其在电信波长的所有三个维度上的占地面积仅为其发射波长的三分之一。我们表明，通过将金属芯移离同轴结构的中心，腔的有效模式体积可以小至 0.0078 × (λ0/na)3，从而导致珀塞尔因子超过 390，调制带宽超过 60GHz。我们进一步表明，可以通过选择适当的基板材料来设计腔 Q 因子随芯移距离的变化趋势。与对称对应物相比，这种移芯同轴纳米腔不仅具有更高的 Q 因子、珀塞尔因子和调制带宽，而且还具有改进的发射方向性，这对于与其他片上组件的耦合至关重要。所提出的纳米发射器还具有在整个核心移动范围内稳定的单模操作的特点，从而产生接近一致的自发发射因子。因此，该器件可以成为低功率光学互连应用的良好候选者。
We present an ultrafast nanoscale light source utilizing a shifted-core coaxial nano-cavity, with a footprint of merely one-third of its emission wavelength in all three dimensions at telecommunication wavelengths. We show that, by shifting the metallic core off center of the coaxial structure, the effective mode volume of the cavity can be as small as 0.0078 × (λ0/na)3, resulting in a Purcell factor over 390 and a modulation bandwidth exceeding 60GHz. We further show that the evolution trend of the cavity Q factor as a function of core-shifting distance can be engineered by choosing proper substrate material. Compared to its symmetric counterpart, this shifted-core coaxial nano-cavity features not only higher Q factor, Purcell factor, and modulation bandwidth but also an improved emission directivity that is essential in its coupling with other on-chip components. The proposed nano-emitter also features robust single mode operation over the entire core-shifting range, resulting in a near-unity spontaneous emission factor. Therefore, this device can be a good candidate for low power optical interconnect applications.