Quantifying the Robustness of Topological Slow Light
Quantifying the Robustness of Topological Slow Light
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DOI：
10.1103/physrevlett.126.027403
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发表时间：
2021-01-14
影响因子：
8.6
通讯作者：
David Garcia, Pedro
中科院分区：
文献类型：
--
作者：
Arregui, Guillermo;Gomis-Bresco, Jordi;David Garcia, Pedro
反向散射平均自由程xi，即沿波导沿着的平均弹道传播长度，量化了慢光对纳米结构的临界尺寸中的不希望的缺陷的抵抗。该品质因数确定了受最小散射损耗影响的可接受的慢光传输与当波导长度L超过xi时的强后向散射引起的相消干涉之间的交叉。在这里，我们计算的反向散射平均自由程的拓扑光子波导的一个特定的和确定的数量的混乱，同样相关的，为一个固定值的群指数n（g），这是相对于真空中的光速的群速度的减速因子。这两个数字的优点，xi和n（g），应考虑在量化的鲁棒性拓扑和传统的（非拓扑）慢光传输在纳米级。否则，任何关于拓扑导光比传统导光性能更好的主张都是不合理的。
The backscattering mean free path xi, the average ballistic propagation length along a waveguide, quantifies the resistance of slow light against unwanted imperfections in the critical dimensions of the nanostructure. This figure of merit determines the crossover between acceptable slow-light transmission affected by minimal scattering losses and a strong backscattering-induced destructive interference when the waveguide length L exceeds xi. Here, we calculate the backscattering mean free path for a topological photonic waveguide for a specific and determined amount of disorder and, equally relevant, for a fixed value of the group index n(g) which is the slowdown factor of the group velocity with respect to the speed of light in vacuum. These two figures of merit, xi and n(g), should be taken into account when quantifying the robustness of topological and conventional (nontopological) slow-light transport at the nanoscale. Otherwise, any claim on a better performance of topological guided light over a conventional one is not justified.