Epsilon-near-zero (ENZ) media disclose the peculiarities of electrodynamics in the limit of infinite wavelength but nonzero frequency for experiments and applications. Theory suggests that wave interaction with obstacles and disturbances dramatically changes in this domain. To investigate the optics of those effects, we fabricated a nanostructured 2D optical ENZ multilayer waveguide that is probed with wavelength-tuned laser light via a nanoscale wave launch configuration. In this experimental framework, we directly optically measure wave propagation and diffraction in a realistic system with the level and scale of imperfection that is typical in nanooptics. As we scan the wavelength from 1.0 to 1.7 μm, we approach the ENZ regime and observe the interference pattern of a microscale Young’s double slit to steeply diverge. By evaluating multiple diffraction orders we experimentally determine the effective refractive index n_eff and its zero-crossing as an intrinsic measured reference, which is in agreement with theoretical predictions. We further verify that the double-slit and specifically placed scattering objects become gradually invisible when approaching the ENZ regime. We also observe that light–matter interaction intensifies toward ENZ and quantify how speckle noise, caused by tiny random imperfections, increasingly dominates the optical response and blue-shifts the cutoff frequency.

中文翻译：

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杨氏双缝，隐形物体和噪声在光学厄普西隆近零实验中的作用

Epsilon近零（ENZ）媒体在实验和应用中公开了在无限波长但非零频率范围内电动力学的特殊性。理论表明，波与障碍物和干扰的相互作用在此领域发生了巨大变化。为了研究这些效应的光学特性，我们制造了一种纳米结构的二维光学ENZ多层波导，该波导通过纳米波发射配置用波长调谐的激光进行探测。在这个实验框架中，我们直接用现实光学系统光学测量波的传播和衍射，并获得纳米光学中典型的缺陷水平和尺度。当我们扫描从1.0到1.7μm的波长时，我们接近ENZ体制，并观察到微尺度杨氏双缝隙的干涉图，从而急剧发散。n _eff及其零交叉点作为内在的测量参考，与理论预测一致。我们进一步验证，在接近ENZ体制时，双狭缝和专门放置的散射物体逐渐变得不可见。我们还观察到，光-物质相互作用向ENZ增强，并量化了由微小的随机缺陷引起的斑点噪声如何逐渐主导光学响应并使截止频率发生蓝移。