Observing the localization of light in space and time by ultrafast second-harmonic microscopy
Observing the localization of light in space and time by ultrafast second-harmonic microscopy
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DOI：
10.1038/nphoton.2012.69
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发表时间：
2012-05-01
期刊：
影响因子：
35
通讯作者：
Lienau, Christoph
中科院分区：
文献类型：
--
作者：
Mascheck, Manfred;Schmidt, Slawa;Lienau, Christoph
多重相干散射和某些散射路径的建设性干涉形成了随机无序介质中经典波和量子波几种显著局域化现象的共同方案(1)。突出的例子是无序导体中的电子传输(2，3)，半导体纳米结构中激子的局域化(4，5)，粗糙金属薄膜中的表面等离子体激元(6，7)或无序介质中的光(8-11)和放大介质(1，12-14)。然而，直接观察本地化过程的基本时空动力学仍然具有挑战性(15)。这尤其适用于发生在极短的飞秒时间尺度和纳米尺度上的光的局部化。在这里，我们结合二次谐波显微镜和少周期时间分辨率来探索光波在随机介质中的时空局域化。我们发现了几飞秒的光子模的寿命和局域光密度的广泛分布，揭示了光的局域化的中心特征。
Multiple coherent scattering and the constructive interference of certain scattering paths form the common scheme of several remarkable localization phenomena of classical and quantum waves in randomly disordered media(1). Prominent examples are electron transport in disordered conductors(2,3), the localization of excitons in semiconductor nanostructures(4,5), surface plasmon polaritons at rough metallic films(6,7) or light in disordered dielectrics(8-11) and amplifying media(1,12-14). However, direct observation of the fundamental spatiotemporal dynamics of the localization process remains challenging(15). This holds true, in particular, for the localization of light occurring on exceedingly short femtosecond timescales and nanometre length scales. Here, we combine second harmonic microscopy with few-cycle time resolution to probe the spatiotemporal localization of light waves in a random dielectric medium. We find lifetimes of the photon modes of several femtoseconds and a broad distribution of the local optical density of states, revealing central hallmarks of the localization of light.