Abstract-Active Terahertz Chiral Metamaterials Based on Phase Transition of Vanadium Dioxide (VO2)

Shengxiang Wang, Lei Kang, Douglas H. Werner,

https://www.nature.com/articles/s41598-017-18472-x

Compared with natural materials, chiral metamaterials have been demonstrated with orders of magnitude stronger chiroptical response, which provides the basis for applications such as ultracompact polarization components and plasmonic-enhanced biosensing. Terahertz chiral metamaterials that allow dynamic polarization control of terahertz waves are of great practical interest, but remain extremely rare. Here, we show that hybrid metamaterials integrated with vanadium dioxide (VO2) exhibiting phase transition can enable dynamically tunable chiroptical responses at terahertz frequencies. In particular, a circular dichroism of ~40° and a maximum polarization rotation of ~200°/λ are observed around 0.7 THz. Furthermore, our study also reveals that the chiroptical response from the proposed metamaterials is strongly dependent on the phase transition of VO2, leading to actively controllable polarization states of the transmitted terahertz waves. This work paves the way for the development of terahertz metadevices capable of enabling active polarization manipulation.

Abstract-A Metamaterial with Dual-Band Perfect Terahertz Transmission

Guochao Wei, Yawei Zheng, Xiran Chen, Zhengpeng Qin, Luman Qin, Nangang Zhang, Kan Liu, Songzhan Li, Shengxiang Wang,

http://iopscience.iop.org/article/10.1088/1757-899X/250/1/012019/meta;jsessionid=965EE1AADFB0F5A6C864A3BFBFF1ABC6.c2.iopscience.cld.iop.org

In recent years, the electromagnetic metamaterial has been development rapidly. Meanwhile, its peculiar electromagnetic properties have been widely studied in the fields of electromagnetism and optics. Compared to conventional natural materials, metamaterials show some unusual phenomena, for example, negative refractive index. Because of their exotic properties, metamaterials have been found with many applications, such as perfect lens, cloaking, solar cells and so on. In this paper, we report a metamaterial with dual-band perfect transmission in terahertz range. By tailoring the periodicity of the unit cell, significantly high transmission can be obtained with the metamaterial. The simulation results show that significant transmission peaks at 3.56THz and 7.16THz with the magnitudes of 99.8% and 99.7%, respectively.