Technion, Israel Institute of Technology, Haifa 32000, Israel.
Physics Department, Queens College and Graduate Center of the City University of New York (CUNY), Flushing, NY 11367, USA.
Science. 2017 Jun 2;356(6341):953-956. doi: 10.1126/science.aah6822.
Anderson localization is an interference effect crucial to the understanding of waves in disordered media. However, localization is expected to become negligible when the features of the disordered structure are much smaller than the wavelength. Here we experimentally demonstrate the localization of light in a disordered dielectric multilayer with an average layer thickness of 15 nanometers, deep into the subwavelength regime. We observe strong disorder-induced reflections that show that the interplay of localization and evanescence can lead to a substantial decrease in transmission, or the opposite feature of enhanced transmission. This deep-subwavelength Anderson localization exhibits extreme sensitivity: Varying the thickness of a single layer by 2 nanometers changes the reflection appreciably. This sensitivity, approaching the atomic scale, holds the promise of extreme subwavelength sensing.
安德森局域化是理解无序介质中波的一个至关重要的干涉效应。然而，当无序结构的特征远小于波长时，局域化预计会变得可以忽略不计。在这里，我们实验演示了在平均层厚为 15 纳米的无序介电多层中光的局域化，深入到亚波长范围。我们观察到强烈的无序诱导反射，表明局域化和渐逝波的相互作用可以导致传输显著减少，或者相反的增强传输特征。这种深亚波长安德森局域化表现出极端的灵敏度：通过将单层厚度变化 2 纳米，可以明显改变反射。这种接近原子尺度的灵敏度有望实现极端的亚波长传感。
