We have constructed and characterized THz phase shifters based on liquid crystals (LCs) with graphene grown by chemical vapor deposition (CVD) and indium-tin-oxide nanowhiskers (ITO NWhs) as transparent conducting electrodes. A graphene-based phase shifter can achieve a phase shift of π/2 at 1.0 THz with the operating voltage of ~2.2 V (rms) as opposed to ~ 5.6 V (rms) for ITO-NWhs-based phase shifter in previous work. On the other hand, 2π phase shift at 1.0 THz was achieved in an ITO-NWhs-based phase shifter with a multi-sandwiched structure by applying ~2.6 V (rms). The low operation voltage of both two kinds of phase shifters imply compatibility of both type of devices with thin-film transistor (TFT) and complementary metal-oxide-semiconductor (CMOS) technologies. The experimental results of phase shifters are in good agreement with the theoretical predictions.

Date Published: 11 March 2015
PDF: 9 pages
Proc. SPIE 9384, Emerging Liquid Crystal Technologies X, 93840Q (11 March 2015); doi: 10.1117/12.2079324

Published in SPIE Proceedings Vol. 9384:
Emerging Liquid Crystal Technologies X
Liang-Chy Chien; Harry J. Coles; Hirotsugu Kikuchi; Ivan I. Smalyukh, Editor(s)