论文标题
在无序活动介质中选择性泵送局部状态
Selective Pumping of Localized States in a Disordered Active Medium
论文作者
论文摘要
强烈散射无序系统中的光散射和定位受底层本征模的性质,特别是它们在系统中的空间扩展。像本地化状态一样,研究安德森(Anderson)的主要挑战之一是很难独立激发这些状态并在样本中的任何地方单独观察它们。模式相互相互作用及其与样品边界的耦合使得将它们隔离并单独成像它们非常具有挑战性。在存在增益的情况下,随机激光发生在阈值以上,激发模式被激发。最近表明,在任何所需的发射波长下,塑造光泵的强度曲线是控制和强制单体模式状态中随机激光的一种非常有效的方法。因此,主动随机媒体提供了一个独特的平台来单独选择模式。通过在强烈散射的随机激光器中使用泵塑形技术,我们成功地单独选择了局部激光模式。随机激光内的光分布的直接成像证实了模式的限制性质,使我们能够阐明关于非热性在主动散射介质中的作用的长期问题,以及非线性对安德森波浪定位的影响。
Light scattering and localization in strongly scattering disordered systems is governed by the nature of the underlying eigenmodes, specially their spatial extension within the system. One of the main challenges in studying experimentally Anderson like localized states resides in the difficulty to excite these states independently and observe them individually anywhere in the sample. The modes mutual interaction and their coupling to the sample boundaries makes it extremely challenging to isolate them spectrally and image them alone. In the presence of gain, random lasing occurs above threshold and lasing modes are excited. It was shown recently that shaping the intensity profile of the optical pump is a very effective way to control and force random lasing in singlemode regime at any desired emission wavelength. Active random media therefore offer a unique platform to select modes individually. By using pump shaping technique in a strongly scattering random laser, we successfully select localized lasing modes individually. Direct imaging of the light distribution within the random laser confirms the confined nature of the modes and enables us to elucidate long standing questions on the role of non-Hermiticity in active scattering media and the influence of nonlinearities on Anderson wave localization.