物理学报2016，Vol.65Issue(8)：080702-1-080702-8,8.DOI:10.7498/aps.65.080702
多功能太赫兹超表面偏振控制器∗
Multifunctional metasurfaces for terahertz p olarization controller
摘要
Abstract
Polarization is one of the basic properties of electromagnetic wave conveying valuable information about signal transmission and sensitive measurements. Manipulations of polarization state and amplitude have aroused a lot of research interest in many different fields, especially in the terahertz (THz) regime. Although many researches on THz polarization controller have been carried out, their transmission losses are still difficult to lower in a broad bandwidth. And there are few reports on THz polarization controller which can rotate the polarization state and split beams at the same time. Multifunctional THz devices are required to meet the needs of the progress of THz technology and its applications. In order to overcome this constraint, semiconductor silicon is integrated into the proposed structure to manipulate the polarization state and the amplitude, because of its optical properties with the external pump light. Here, according to the electromagnetic resonance between split rings and silicon rings in Fabry-Pérot-like cavity, we propose a metasurfaces-based terahertz polarization controller. The unite cell structure is composed of metal grids-split ring/Si ring-metal grids spaced by silica layers. By using the finite element method in CST Microwave Studio, we simulate the transport and polarization properties under different conditions. The results show that a linear polarization state can be nearly perfectly converted into its orthogonal one from 0.39 to 1.11 THz with a transmission loss of 1 dB, which fits well to the one of multiple-beam interference theory. Then we study the properties of the proposed metasurface structure for oblique incidence. The property of rotating polarization basically keeps stable even at an incident angle of 60◦ from 0.52 to 1.05 THz. At the end of the paper, the polarization splitting feature of the device is discussed in the THz regime. The results demonstrate that the transmitted and reflected beam power of the device can be tuned by changing the pump light power. The modulation depths of two beams reach more than 90% at 0.5 THz. It is worth noting that the proposed structure can not only rotate the polarization state of transmitted light in a broad bandwidth of 0.72 THz, but also modulate the transmitted and reflected beam power with a wide modulation depth. It can be used as a broad-band, low-loss and tunable terahertz polarization controller which is also insensitive to the incident angle. So it meets the requirements in THz communication, spectrum detection and imaging systems.关键词
太赫兹/人工超表面/偏振转换/偏振分束Key words
terahertz/metasurfaces/polarization conversion/polarization splitting引用本文复制引用
杨磊,范飞,陈猛,张选洲,常胜江..多功能太赫兹超表面偏振控制器∗[J].物理学报,2016,65(8):080702-1-080702-8,8.基金项目
国家重点基础研究发展计划(批准号:2014CB339800)、国家自然科学基金(批准号:61171027,61505088)、天津市自然科学基金(批准号:15JCQNJC02100)和国家高技术研究发展计划(批准号:2011AA010205)资助的课题.* Project supported by the National Basic Research Program of China (Grant No.2014CB339800), the National Natural Science Foundation of China (Grant Nos.61171027,61505088), the Natural Science Foundation of Tianjin, China (Grant No.15JCQNJC02100), and the National High Technology Research and Development Program of China (Grant No.2011AA010205) （批准号:2014CB339800）
