Center of Excellence on Applied Electromagnetic Systems, School of Electrical and Computer Engineering, College of Engineering, University of Tehran, Tehran, Iran.
Microwave and Antenna Group (MAG), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
Sci Rep. 2021 Jan 21;11(1):1953. doi: 10.1038/s41598-021-81091-0.
Far field superlensing of light has generated great attention in optical focusing and imaging applications. The capability of metamaterials to convert evanescent waves to propagative waves has led to numerous proposals in this regard. The common drawback of these approaches is their poor performance inside strongly scattering media like biological samples. Here, we use a metamaterial structure made out of aluminum nanorods in conjunction with time-reversal technique to exploit all temporal and spatial degrees of freedom for superlensing. Using broadband optics, we numerically show that this structure can perform focusing inside biological tissues with a resolution of λ/10. Moreover, for the imaging scheme we propose the entropy criterion for the image reconstruction step to reduce the number of required optical transducers. We propose an imaging scenario to reconstruct the spreading pattern of a diffusive material inside a tissue. In this way super-resolution images are obtained.
远场超透镜在光学聚焦和成像应用中引起了极大的关注。超材料将消逝波转换为传播波的能力在这方面催生了众多的方案。这些方法的共同缺点是在像生物样本这样的强散射介质内部性能较差。在这里，我们使用由铝纳米棒制成的超材料结构结合时间反转技术来利用超透镜的所有时间和空间自由度。使用宽带光学器件，我们通过数值模拟表明，该结构可以在具有 λ/10 分辨率的生物组织内进行聚焦。此外，对于我们提出的成像方案，我们建议在图像重建步骤中使用熵准则来减少所需光学换能器的数量。我们提出了一种成像方案来重建组织内扩散物质的扩散模式。通过这种方式获得了超分辨率图像。
