论文标题
光纤尖端上的等离子随机激光
Plasmonic random laser on an optical fiber tip
论文作者
论文摘要
随机激光是由于来自多个散射中心的相干光学反馈而发生的。在这里，我们证明了等离激元的金纳米级是有效的光散射中心，在其纳米叶片上表现出强场增强，这有助于具有低光谱阈值的非常狭窄的带宽和高度放大的相干随机激光。首先，通过将等离子金纳米纳斯塔杆嵌入若丹明6g染料增益培养基中，我们观察到一系列非常狭窄的随机激光峰，全宽度为半最大〜0.8 nm。相比之下，游离的若丹明6G染料分子仅表现出一个单个扩增的自发发射峰，较大的线宽为6 nm。用金纳米纳斯塔尔的染料的激光阈值比自由染料低两倍。此外，通过将单模光纤的尖端涂上金纳米仪，我们通过纤维演示了一系列随机激光信号的集合，可以轻松地引导和分析。时间分辨测量结果表明，在激光阈值上方的排放率显着增加，表明刺激的排放过程。我们的研究提供了一种在纳米级中产生随机激光的方法，该纳米级值较低，可以轻松地收集和指导，这有望在遥感，信息处理和片上相干光源中进行一系列潜在的应用。
Random lasing occurs as the result of a coherent optical feedback from multiple scattering centers. Here, we demonstrate that plasmonic gold nanostars are efficient light scattering centers, exhibiting strong field enhancement at their nanotips, which assists a very narrow bandwidth and highly amplified coherent random lasing with a low lasing threshold. First, by embedding plasmonic gold nanostars in a rhodamine 6G dye gain medium, we observe a series of very narrow random lasing peaks with full-width at half-maximum ~ 0.8 nm. In contrast, free rhodamine 6G dye molecules exhibit only a single amplified spontaneous emission peak with a broader linewidth of 6 nm. The lasing threshold for the dye with gold nanostars is two times lower than that for a free dye. Furthermore, by coating the tip of a single-mode optical fiber with gold nanostars, we demonstrate a collection of random lasing signal through the fiber that can be easily guided and analyzed. Time-resolved measurements show a significant increase in the emission rate above the lasing threshold, indicating a stimulated emission process. Our study provides a method for generating random lasing in the nanoscale with low threshold values that can be easily collected and guided, which promise a range of potential applications in remote sensing, information processing, and on-chip coherent light sources.
