Toward Super-Resolution Imaging at Green Wavelengths Employing Stratified Metal-Insulator Metamaterials
Toward Super-Resolution Imaging at Green Wavelengths Employing Stratified Metal-Insulator Metamaterials
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DOI：
10.3390/photonics2020468
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发表时间：
2015-06-01
期刊：
影响因子：
2.4
通讯作者：
Iwanaga, Masanobu
中科院分区：
文献类型：
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作者：
Iwanaga, Masanobu
超材料是本世纪发展迅速的亚波长结构材料，具有实现负折射、隐形和超分辨率等新现象的各种潜力。在365 ~ 405 nm的紫外和紫外光波段，实验证明了金属薄膜超分辨率图像转移的理论建议。然而，光学成像的最优选波长是500纳米左右的绿色波长，因为光学显微镜在生物技术领域得到了最广泛的利用。为了使MM的超分辨率技术更加实用，我们提出了一种分层金属绝缘体MM的设计，该MM具有绿色波长的超分辨率图像传输模式，我们在这里称之为超模式。该设计仅假设Ag和SiO2为组成材料，并采用bloch状态分析，该分析基于金属绝缘体mm的严格传递矩阵方法。数值验证了所设计的层状金属绝缘体超材料（SMIM）能够在绿色波长形成超分辨率图像，并对光学损耗的降低进行了研究。讨论了布洛赫状态分析和金属绝缘子mm中常用的有效介质模型的结果，表明布洛赫状态分析更适合再现实验数据。
Metamaterials (MMs) are subwavelength-structured materials that have been rapidly developed in this century and have various potentials to realize novel phenomena, such as negative refraction, cloaking and super-resolution. Theoretical proposals for super-resolution image transfer using metallic thin films were experimentally demonstrated at ultraviolet and violet wavelengths from 365 to 405 nm. However, the most preferred wavelengths of optical imaging are green wavelengths around 500 nm, because optical microscopy is most extensively exploited in the area of biotechnology. In order to make the super-resolution techniques using MMs more practical, we propose the design of a stratified metal-insulator MM that has super-resolution image transfer modes at green wavelengths, which we here call hyper modes. The design assumed only Ag and SiO2 as constituent materials and was found employing Bloch-state analysis, which is based on a rigorous transfer-matrix method for the metal-insulator MMs. It is numerically substantiated that the designed stratified metal-insulator metamaterial (SMIM) is capable of forming super-resolution images at the green wavelengths, and optical loss reduction is also studied. We discuss the results derived by the Bloch-state analysis and by effective medium models usually used for the metal-insulator MMs and show that the Bloch-state analysis is more suitable to reproduce the experimental data.