Paper
16 December 2022 Terahertz liquid crystal phase shifter controlled by graphene transparent electrode
Author Affiliations +
Proceedings Volume 12501, Seventeenth National Conference on Laser Technology and Optoelectronics; 1250118 (2022) https://doi.org/10.1117/12.2656596
Event: Seventeenth National Conference on Laser Technology and Optoelectronics, 2022, Shanghai, China
Abstract
Graphene films are characterized by high electrical conductivity and high optical transmittance. In this paper, we mixed graphene solution and polyvinyl alcohol (PVA) solution to make different concentrations of graphene solution. The electrical conductivity, optical transmittance, and phase shift of multilayer graphene films were measured in the THz range by coating graphene solution on the substrate. According to experimental results, the following conclusions are drawn: the film with a larger proportion of graphene has a smaller square resistance, that is, a better conductivity, a smaller transmittance, and a phase shift in the terahertz range under the same thickness. Subsequently, the solution made of 1:1.75 PVA and graphene solution was coated on the outside of the glass sheets containing E7 and HTD liquid crystals, respectively. The distance between the two glass sheets was 800um, which was the thickness of the liquid crystals. Then, a magnetic field is added along one side of the glass sheet (defined as the X direction). Through experiments, it is found that when the voltage is added to 100V (130V), the orientation of E7 (or HTD) liquid crystal can completely change the direction of the electric field. And in the case of the only magnetic field, E7 (or HTD) liquid crystal produces 0.5π phase difference corresponding frequency is 0.8THz (0.6THz), π phase difference corresponding frequency is 1.4THz (1.0THz).
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Song-Lin Jiang, Yun-Yun Ji, and Fei Fan "Terahertz liquid crystal phase shifter controlled by graphene transparent electrode", Proc. SPIE 12501, Seventeenth National Conference on Laser Technology and Optoelectronics, 1250118 (16 December 2022); https://doi.org/10.1117/12.2656596
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KEYWORDS
Graphene

Liquid crystals

Terahertz radiation

Polyvinyl alcohol

Phase shifts

Transmittance

Electric fields

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