Abstract-Super terahertz phase shifter achieving high transmission and large modulation depth

Shuai Li, Jing Wang, Hao Tian, Li Li, Jianlong Liu, Guan Chao Wang, Jiaojiao Gao, Chengpeng Hu, and Zhongxiang Zhou

https://www.osapublishing.org/ol/abstract.cfm?uri=ol-45-10-2834

We propose an industrial-grade liquid-crystal-based terahertz (THz) 2π-phase shifter with predictable ultra-high amplitude transmittance. The phase retardation reaches 360.5° at 1.68 THz by analyzing the birefringence of liquid crystal (LC), and the amplitude transmittance in 0.3–1.5 THz is over 83%. More than 91.5% transmittance can be reached by decreasing the scattering of the THz wave in the dynamic deflection process of LC molecules, and that is close to the transmittance limit of quartz-based devices. This millimeter-thick phase shifter reaches full phase modulation and ultra-high transmittance in a broad THz band, is easy to be integrated in a quasi-optical system with a compact size and can be utilized as a wave plate, even an element in a THz phased array.

© 2020 Optical Society of America

Abstract-Liquid crystal terahertz modulator with plasmon-induced transparency metamaterial

Jing Wang, Hao Tian, Yu Wang, Xueyan Li, Yujie Cao, Li Li, Jianlong Liu, Zhongxiang Zhou

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-26-5-5769

An electrically tunable terahertz (THz) modulator with large modulation depth and low insertion loss is performed with liquid crystal (LC) metamaterial. The modulation depth beyond 90% and insertion loss below 0.5 dB are achievable at normal incidence by exploiting plasmon-induced transparency (PIT) effect. The PIT spectra can be manipulated by actively controlling the interference between dipole mode and nonlocal surface-Bloch mode with LC. The incident angle tuning effect on PIT spectra shows that the large modulation depth and low insertion loss can remain over a wide range of working angles. The superior property and simplicity of design make this modulator promising in advanced terahertz communication.

© 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Abstract-The terahertz characteristics of a sandwich type microplasma structure

Ruilin Gao¹, Chengxun Yuan¹, Ying Wang¹, Zhongxiang Zhou¹, Dewei Gong¹, Yuan Fang¹, and Xianwei Rong²

¹Department of Physics, Harbin Institute of Technology, Harbin, Heilongjiang 150001, China
²School of Physics and Electronic Engineering, Harbin Normal University, Harbin, Heilongjiang 150025, China 

http://jap.aip.org/resource/1/japiau/v114/i12/p123302_s1?isAuthorized=no

Recently, major technical advances in developing intense terahertz (THz) sources have provided us with new opportunities to investigate characteristics of a high density microplasma with THz waves. In this paper, a simple sandwich type microplasma model is established. The finite-difference time-domain method using Z-transforms is utilized to simulate the characteristics of reflection, transmission, and absorption of THz waves in this microplasma structure. The effects of both the microplasma width and the permittivity of the outer medium on the propagation are analyzed, and the results show that the THz waves can be greatly influenced and modulated by the structure of the plasma slab and the outer medium. It is demonstrated that such plasma metamaterials exhibit some extraordinary properties in THz frequency range.

© 2013 AIP Publishing LLC

Article Outline

1. INTRODUCTION
2. FDTD ALGORITHM
   1. Z-transforms FDTD method
   2. Validity and precision of Z-transforms FDTD
3. SIMULATION RESULTS AND DISCUSSION
   1. Establishment of the model and choice of the parameters
   2. The effects of plasma layer thickness on the propagation of THz waves
   3. The modulation effects of dielectric plates on the propagation of THz waves
4. CONCLUSION