Artificial dielectric stepped-refractive-index lens for the terahertz region
Artificial dielectric stepped-refractive-index lens for the terahertz region
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DOI：
10.1364/oe.26.003702
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发表时间：
2018-02-05
期刊：
影响因子：
3.8
通讯作者：
Mittleman, Daniel M.
中科院分区：
文献类型：
--
作者：
Hernandez-Serrano, A. I.;Mendis, Rajind;Mittleman, Daniel M.
在本文中，我们从理论和实验上证明了一个阶梯折射率会聚透镜的平行堆叠的金属板的太赫兹频率的基础上人工晶体。该透镜由非均匀间隔的金属板堆叠组成，形成平行板波导（PPWG）的镜像对称阵列。该设备的操作基于PPWG的TE 1模式。TE 1模的有效折射率是工作频率和PPWG板之间间距的函数。通过改变板之间的间距，我们可以修改构成透镜的每个单独PPWG中的结构的局部折射率，从而在多堆叠结构上产生阶梯式折射率分布。理论和实验结果表明，在0.18THz的设计频率下，该结构能够将直径为1cm的光束聚焦成小于4mm的线焦点。这种结构表明，这种人工介质的概念是一个重要的技术，为下一代太赫兹器件的制造。(c)2018年美国光学学会根据OSA开放获取出版协议的条款
In this paper we theoretically and experimentally demonstrate a stepped-refractiveindex convergent lens made of a parallel stack of metallic plates for terahertz frequencies based on artificial dielectrics. The lens consist of a non-uniformly spaced stack of metallic plates, forming a mirror-symmetric array of parallel-plate waveguides (PPWGs). The operation of the device is based on the TE1 mode of the PPWG. The effective refractive index of the TE1 mode is a function of the frequency of operation and the spacing between the plates of the PPWG. By varying the spacing between the plates, we can modify the local refractive index of the structure in every individual PPWG that constitutes the lens producing a stepped refractive index profile across the multi stack structure. The theoretical and experimental results show that this structure is capable of focusing a 1 cm diameter beam to a line focus of less than 4 mm for the design frequency of 0.18 THz. This structure shows that this artificial-dielectric concept is an important technology for the fabrication of next generation terahertz devices. (c) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement