Terahertz polarization conversion and sensing with double-layer chiral metasurface  

作　　者：Zi-Yang Zhang Fei Fan Teng-Fei Li Yun-Yun Ji Sheng-Jiang Chang 张子扬;范飞;李腾飞;冀允允;常胜江(Institute of Modern Optics,Nankai University,Tianjin 300350,China;Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology,Tianjin 300350,China)

机构地区：[1]Institute of Modern Optics,Nankai University,Tianjin 300350,China [2]Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology,Tianjin 300350,China

出　　处：《Chinese Physics B》2020年第7期164-171,共8页中国物理B（英文版）

基　　金：Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0701000);the National Natural Science Foundation of China(Grant Nos.61971242,61831012,and 61671491);the Natural Science Foundation of Tianjin City,China(Grant No.19JCYBJC16600);the Young Elite Scientists Sponsorship Program by Tianjin,China(Grant No.TJSQNTJ-2017-12).

摘　　要：The terahertz(THz)resonance,chirality,and polarization conversion properties of a double-layer chiral metasurface have been experimentally investigated by THz time domain spectroscopy system and polarization detection method.The special symmetric geometry of each unit cell with its adjacent cells makes a strong chiral electromagnetic response in this metasurface,which leads to a strong polarization conversion effect.Moreover,compared with the traditional THz transmission resonance sensing for film thickness,the polarization sensing characterized by polarization elliptical angle(PEA)and polarization rotation angle(PRA)shows a better Q factor and figure of merit(FoM).The results show that the Q factors of the PEA and PRA reach 43.8 and 49.1 when the interval film is 20µm,while the Q factor of THz resonance sensing is only 10.6.And these PEA and PRA can play a complementary role to obtain a double-parameter sensing method with a higher FoM,over 4 times than that of resonance sensing.This chiral metasurface and its polarization sensing method provide new ideas for the development of high-efficiency THz polarization manipulation,and open a window to the high sensitive sensing by using THz polarization spectroscopy.

关 键 词：TERAHERTZ chiral metasurface polarization conversion SENSING 

分 类 号：O441.4[理学—电磁学] TP212[理学—物理]