Realization of ultrahigh refractive index in terahertz region by multiple layers coupled metal ring metamaterials

ABSTRACT

We report a polarization-independent unnaturally high refractive index metamaterial. It is found that the effective permittivity of the designed metamaterial can be drastically increased by the capacitive coupling effect. Also, the effective permeability of metamaterial can be increased by reducing the diamagnetic effect by designing a thin structure. In our work, the single-layer multi-band high refractive index metamaterials with a peak achieving to 26.8 at 0.9 THz is demonstrated. Furthermore, the three-dimensional metamaterial possessing high refractive index more than 85 around 0.91 THz can be constructed by a double-layer tricyclic structure. Ultrabroadband and ultrahigh refractive index of designed metamaterials can be obtained by multilayer coupling effect. In addition, the polarization-independent property and wide-angle performance of high refractive index metamaterial are exhibited.

KEYWORDS:

• Metamaterial
• optical material
• terahertz
• high refractive index

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by National Key R&D Program of China [grant number 2018YFF01013005], Natural Science Foundation of Zhejiang Province [grant number LY17F050009], National Natural Science Foundation of China (NSFC) [grant numbers 61875159, 61405182].

Notes on contributors

Bo Fang

Bo Fang is associate professor of China Metrology University, master’s tutor, graduated from the Department of Applied Physics, Southwest Jiaotong University, and his PhD degree from School of Optoelectronic Information and Computer Engineering, University of Shanghai for Science and Technology.

Zhiyu Cai

Zhiyu Cai is a graduate student of China Metrology University.

Yandong Peng

Peng Yandong, male, associate professor, Shandong Tai’an, master’s tutor. In June 2011, he received his PhD in Optics from the Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences. Since July 2011, he has worked in the School of Science and Electronic Communication and Physics of Shandong University of Science and Technology.

Chenxia Li

Chenxia Li is an associate professor at China Metrology University and graduated from Shanghai University of Technology in 2009.

Zhi Hong

Zhi Hong received his bachelor’s and master’s degrees in electrical engineering from Zhejiang University in 1984 and 1987, and his PhD in optical engineering from Zhejiang University in 2001. 1987.7–2005.12 State Key Laboratory of Modern Optical Instruments, Zhejiang University (2001 Researcher, 2002 Optical Engineering Doctoral Supervisor). 2006.1–Researcher, School of Mechanical and Electrical Engineering, China Institute of Metrology, Director of Institute of Technology and Applications, China Institute of Metrology. In 1999 and 2000, he went to the Berlin University of Technology in cooperation research, and visited professors from Alberta University, Canada, from 2003 to 2003.12. 2007.8–2007.11 Visiting Professor of the Terahertz Research Center, Rensselaer Institute of Technology, USA.

Xufeng Jing

Xufeng Jing is associate professor of China Metrology University, master’s tutor. He got his PhD in Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences in 2011.