Tao Chung-Wei, Yen Ta-Jen, Huang Tsung-Yu
Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, 30013, Taiwan, ROC.
Department of Materials Engineering, Ming Chi University of Technology, New Taipei City, 24301, Taiwan, ROC.
Sci Rep. 2020 Mar 24;10(1):5296. doi: 10.1038/s41598-020-62243-0.
Constrained by the diffraction limit, a lens can only resolve features larger than half of the incident wavelength owing to the decaying nature of evanescent waves. Several novel devices have been proposed, for example, superlenses and hyperlenses to break this limit. In this work, we present a flat hyperlens composed of silver nanowires embedded in a modified anodic aluminum oxide (AAO) template to demonstrate subwavelength imaging. Measurement conducted by the near-field scanning optical microscope at 633 nm suggests that our proposed flat hyperlens can indeed achieve sub-wavelength imaging with a resolution down to 0.34λ and 0.25λ along two orthogonal directions. Furthermore, to confirm the resolution limit of the flat hyperlens, numerical simulations were performed at the incident wavelengths of 633 and 365 nm, and the corresponding resolution were 0.19λ and 0.3λ, respectively, thus paving a route for sub-wavelength photolithography.
由于倏逝波的衰减特性，受衍射极限的限制，透镜只能分辨大于入射波长一半的特征。已经提出了几种新型器件，例如超透镜和超颖透镜来打破这一限制。在这项工作中，我们展示了一种由嵌入改性阳极氧化铝（AAO）模板中的银纳米线组成的平面超颖透镜，以实现亚波长成像。由近场扫描光学显微镜在633 nm波长下进行的测量表明，我们提出的平面超颖透镜确实可以实现亚波长成像，在两个正交方向上的分辨率分别低至0.34λ和0.25λ。此外，为了确定平面超颖透镜的分辨率极限，在633和365 nm的入射波长下进行了数值模拟，相应的分辨率分别为0.19λ和0.3λ，从而为亚波长光刻铺平了道路。
