Abstract-Electrically tunable superconducting terahertz metamaterial with low insertion loss and high switchable ratios

Chun Li1, Caihong Zhang1,a), Guoliang Hu1, Gaochao Zhou1, Shoulu Jiang1, Chengtao Jiang1, Guanghao Zhu1, Biaobing Jin1,b), Lin Kang1,Weiwei Xu1, Jian Chen1 and Peiheng Wu1


1 Research Institute of Superconductor Electronics (RISE), School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
a) Electronic mail: chzhang@nju.edu.cn
b) Electronic mail: bbjin@nju.edu.cn
Appl. Phys. Lett. 109, 022601 (2016); http://dx.doi.org/10.1063/1.4955454

http://scitation.aip.org/content/aip/journal/apl/109/2/10.1063/1.4955454

With the emergence and development of artificially structured electromagnetic materials, active terahertz (THz) metamaterial devices have attracted significant attention in recent years. Tunability of transmission is desirable for many applications. For example, short-range wireless THz communications and ultrafast THz interconnects require switches and modulators. However, the tunable range of transmission amplitude of existing THz metamaterial devices is not satisfactory. In this article, we experimentally demonstrate an electrically tunable superconducting niobium nitride metamaterial device and employ a hybrid coupling model to analyze its optical transmission characteristics. The maximum transmission coefficient at 0.507 THz is 0.98 and decreases to 0.19 when the applied voltage increases to 0.9 V. A relative transmittance change of 80.6% is observed, making this device an efficient narrowband THz switch. Additionally, the frequency of the peak is red shifted from 0.507 to 0.425 THz, which means that the device can be used to select the frequency. This study offers an alternative tuning method to existing optical, thermal, magnetic-field, and electric-field tuning, delivering a promising approach for designing active and miniaturized THz devices.