Super terahertz phase shifter achieving high transmission and large modulation depth

• Published in: Optics letters Vol. 45; no. 10; p. 2834
• Main Authors: Li, Shuai, Wang, Jing, Tian, Hao, Li, Li, Liu, Jianlong, Wang, Guan Chao, Gao, Jiaojiao, Hu, Chengpeng, Zhou, Zhongxiang
• Format: Journal Article
• Language: English
• Published: United States 15.05.2020
• ISSN: 1539-4794
• DOI: 10.1364/ol.393571

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.