Department of Chemistry, ‡Department of Physics and Astronomy, ∥Department of Electrical and Computer Engineering, Laboratory for Nanophotonics, Rice University , Houston, Texas 77005, United States.
Nano Lett. 2014 Jun 11;14(6):3628-33. doi: 10.1021/nl501363s. Epub 2014 May 12.
Noble metal nanowires are excellent candidates as subwavelength optical components in miniaturized devices due to their ability to support the propagation of surface plasmon polaritons (SPPs). Nanoscale data transfer based on SPP propagation at optical frequencies has the advantage of larger bandwidths but also suffers from larger losses due to strong mode confinement. To overcome losses, SPP gain has been realized, but so far only for weakly confined SPPs in metal films and stripes. Here we report the demonstration of gain for subwavelength SPPs that were strongly confined in chemically prepared silver nanowires (mode area = λ(2)/40) using a dye-doped polymer film as the optical gain medium. Under continuous wave excitation at 514 nm, we measured a gain coefficient of 270 cm(-1) for SPPs at 633 nm, resulting in partial SPP loss compensation of 14%. This achievement for strongly confined SPPs represents a major step forward toward the realization of nanoscale plasmonic amplifiers and lasers.
贵金属纳米线是小型设备中亚波长光学组件的理想候选材料，因为它们能够支持表面等离激元极化激元 (SPP) 的传播。基于 SPP 在光频传播的纳米级数据传输具有更大带宽的优势，但由于强模式限制，也会遭受更大的损耗。为了克服损耗，已经实现了 SPP 的增益，但到目前为止，仅在金属薄膜和条带中弱限制的 SPP 中实现了增益。在这里，我们报告了在使用掺杂染料的聚合物薄膜作为光学增益介质的情况下，在化学制备的银纳米线中（模式面积 = λ(2)/40）对亚波长 SPP 进行强限制时实现增益的演示。在 514nm 的连续波激发下，我们在 633nm 处测量到 SPP 的增益系数为 270cm(-1)，导致 SPP 的部分损耗补偿为 14%。对于强限制 SPP 的这一成就代表了朝着实现纳米级等离子体放大器和激光器迈出的重要一步。
