Co-existence of strongly and weakly localized random laser modes
Co-existence of strongly and weakly localized random laser modes
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DOI：
10.1038/nphoton.2009.67
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发表时间：
2009-05-01
期刊：
影响因子：
35
通讯作者：
Kalt, Heinz
中科院分区：
文献类型：
--
作者：
Fallert, Johannes;Dietz, Roman J. B.;Kalt, Heinz
最近关于随机激光的理论工作预测，窄激光尖峰的发生可以由光的局域模式和扩展模式引起（1-3）。在氧化锌纳米颗粒粉末中观察到了典型的随机激光尖峰（4），但识别这种模式的可能局部化程度迄今为止一直是一个悬而未决的问题（5）。在这封信中，我们提出了一个实验程序，直接提取本地化的模式。这种方法依赖于氧化锌粉末的微结构领域的调查，这也允许通过扫描电子显微镜直接关联到亚波长粒子的合奏的局部结构特性。我们发现，激光从本地和扩展模式可以同时观察到。我们的观察也证实了局域模比扩展模具有更低的损耗率的预测（5）。
Recent theoretical work on random lasing predicts that the occurrence of narrow lasing spikes can be caused by both localized and extended modes of light(1-3). Typical random lasing spikes have been observed in powders of zinc oxide nanoparticles(4), but identifying the possible degrees of localization of such modes has until now been an open issue(5). In this Letter we present an experimental procedure that directly extracts the area of localization of the modes. This method relies on the investigation of micro-structured fields of zinc oxide powder, which also allows direct correlation to the local structural properties of the ensemble of subwavelength particles by scanning electron microscopy. We find that lasing from both localized and extended modes can be observed simultaneously. Our observation also corroborates the prediction that localized modes have a lower loss rate than that of extended modes(5).