激发端口可电切换的单向类电磁诱导透明效应  

Unidirectional Electromagnetically Induced Transparency-Like Effect with Electrically Switchable Excitation Port

作　　者：冉佳 张思文 王文昌 郝宏刚[1,3] 谭菲[1] 陈永强 Ran Jia;Zhang Siwen;Wang Wenchang;Hao Honggang;Tan Fei;Chen Yongqiang(School of Optoelectronic Engineering,Chongqing University of Posts and Telecommunications,Chongqing 400065,China;Postdoctoral Research Center of Chongqing Key Laboratory of Photoelectronic Information Sensing and Transmitting Technology,Chongqing University of Posts and Telecommunications,Chongqing 400065,China;Institute for Advanced Sciences,Chongqing University of Posts and Telecommunications,Chongqing 400065,China;School of Physical Science and Technology,Suzhou University of Science and Technology,Suzhou 215009,Jiangsu,China)

机构地区：[1]重庆邮电大学光电工程学院,重庆400065 [2]重庆邮电大学光电信息感测与传输技术重庆市重点实验室博士后科研工作站,重庆400065 [3]重庆邮电大学高等研究院,重庆400065 [4]苏州科技大学物理科学与技术学院,江苏苏州215009

出　　处：《光学学报》2023年第21期246-254,共9页Acta Optica Sinica

基　　金：重庆市自然科学基金(cstc2020jcyj-msxmX0603)。

摘　　要：具有非对称电磁响应特性的单向类电磁诱导透明效应(EIT-like)是超材料领域重要的研究课题之一,然而目前缺少可动态切换的单向EIT-like实现手段。基于此,提出一种利用二端口的微带谐振腔与两个开口谐振环之间的耦合作用构造单向EIT-like的方法,只有特定端口能够激发出EIT-like效应,其非对称反射系数对比度达到98.7%。在此基础上,结合可调的复合左右手传输线,对微带谐振腔与开口谐振环间的耦合情况进行动态调控,从而改变单向EIT-like的激发端口,实现了激发端口可电切换的单向EIT-like,推动EIT-like在光学存储、光调制、传感等方面的应用。Methods We take Rogers RT5880 copper-clad substrate with a thickness of 1.57 mm as the substrate of the microstrip cavity and CRLH-TLs.The thickness of the copper layer is 0.035 mm.A Fabry-Perot(FP)cavity is formed inside a microstrip line.Two SRRs are placed in the cavity and located at the antinode and node of the electromagnetic field in the FP cavity respectively to construct a unidirectional EIT-like structure.The excitation port of the EIT-like effect is determined by the sequence of the antinode and node in the FP cavity.Tunable composite right/left-handed transmission lines(CRLH-TLs)loaded with varactors are added at the two ends of the FP cavity(marked as left and right CRLH-TLs respectively)to change the electromagnetic field distribution in the cavity.By optimizing all parameters,the electrical lengths of CRLH-TLs are quarter wavelength and half wavelength respectively under different bias voltages.Therefore,since the distribution of the nodes and antinodes in the cavity can be switched by changing the electric length of the CRLHTLs,the sequence of the antinode and node where the two split ring resonators(SRRs)lie in the cavity is also switched,which leads to a switched EIT-like excitation port.Finally,a sample is fabricated and tested to validate the unidirectional EIT-like effect with the electrically switchable excitation port.Results and Discussions This structure realizes the unidirectional EIT-like effect to bring a unidirectional reflection with high contrast ratio.It is validated both in simulation and experiments that the contrast ratio of the unidirectional reflection can reach more than 95%,and the excitation port of the unidirectional EIT-like effect is determined by the sequence of nodes and antinodes in the FP cavity.The capacitance of the varactors in the CRLH-TLs varies along with the bias voltage.Thus,different bias voltages are simulated by setting different capacitance values.In case I,the capacitance of varactors in the left CRLH-TLs is set as 2.5 pF(Csl=2.5 pF)and that in the right

关 键 词：类电磁诱导透明 复合左右手传输线 微带谐振腔 开口谐振环 单向反射 

分 类 号：O436[机械工程—光学工程]