Twisted Nematic Liquid Crystal Based Terahertz Phase Shifter with Crossed Indium Tin Oxide Finger Type Electrodes

Anup Kumar Sahoo, Chan Shan Yang, Osamu Wada, Ci Ling Pan*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

We demonstrate indium-tin-oxide (ITO) finger-type pattern (FTP) as an effective transparent conducting electrode for terahertz (THz) application. The average transmittance of ITO-FTP is as high as 85% in the frequency range of 0.2-1.2 THz. A pair of fused silica substrates with ITO-FTP was employed for constructing an electrically tunable twisted nematic liquid crystal (LC) based THz phase shifter. The cross-orientation pair of ITO-FTPs served as wavelength-insensitive and transparent electrodes for the LC layer. A maximum phase shift exceeding π/2 at 1.2 THz was demonstrated for a device with a 600-μm-thick LC cell. The required driving voltage for quarter-wave operation and threshold voltage were 5.3 and 0.8 VRMS, respectively. Performance of the THz phase shifter is discussed by defining a figure of merit (FOM) for LC-based THz shifters and compared with previously reported devices.

Original languageEnglish
Article number8727968
Pages (from-to)399-408
Number of pages10
JournalIEEE Transactions on Terahertz Science and Technology
Volume9
Issue number4
DOIs
Publication statusPublished - 2019 Jul

Keywords

  • Birefringence
  • liquid-crystal (LC) devices
  • nanomaterials
  • phase shift
  • spectroscopy
  • terahertz (THz)
  • transparent conductive coatings

ASJC Scopus subject areas

  • Radiation
  • Electrical and Electronic Engineering

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