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

doi:10.1109/TTHZ.2019.2920614

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

Graduate Institute of Electro-Optical Engineering

Research output: Contribution to journal › Article › peer-review

15 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 V_RMS, 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 language	English
Article number	8727968
Pages (from-to)	399-408
Number of pages	10
Journal	IEEE Transactions on Terahertz Science and Technology
Volume	9
Issue number	4
DOIs	https://doi.org/10.1109/TTHZ.2019.2920614
Publication status	Published - 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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10.1109/TTHZ.2019.2920614

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

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.",

keywords = "Birefringence, liquid-crystal (LC) devices, nanomaterials, phase shift, spectroscopy, terahertz (THz), transparent conductive coatings",

author = "Sahoo, {Anup Kumar} and Yang, {Chan Shan} and Osamu Wada and Pan, {Ci Ling}",

note = "Funding Information: Manuscript received February 14, 2019; revised May 26, 2019; accepted May 27, 2019. Date of publication June 3, 2019; date of current version July 1, 2019. This work was supported by Science Park R&D Endeavor Project with ACE Biomedical Solution Company Ltd. (Project number 106A33), Zhubei City, Hsinchu County, Taiwan (R.O.C) and other grants by Ministry of Science and Technology (Project number MOST 108-2923-E-007-002-, MOST 106-2112-M-007-022-MY2, and MOST 104-2221-E-007-093-MY3), Taiwan. (Anup Kumar Sahoo and Chan-Shan Yang contributed equally to this work.) (Corresponding author: Ci-Ling Pan.) A. K. Sahoo is with the Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (e-mail: anup140387@gmail.com). Publisher Copyright: {\textcopyright} 2011-2012 IEEE.",

year = "2019",

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T1 - Twisted Nematic Liquid Crystal Based Terahertz Phase Shifter with Crossed Indium Tin Oxide Finger Type Electrodes

AU - Sahoo, Anup Kumar

AU - Yang, Chan Shan

AU - Wada, Osamu

AU - Pan, Ci Ling

N1 - Funding Information: Manuscript received February 14, 2019; revised May 26, 2019; accepted May 27, 2019. Date of publication June 3, 2019; date of current version July 1, 2019. This work was supported by Science Park R&D Endeavor Project with ACE Biomedical Solution Company Ltd. (Project number 106A33), Zhubei City, Hsinchu County, Taiwan (R.O.C) and other grants by Ministry of Science and Technology (Project number MOST 108-2923-E-007-002-, MOST 106-2112-M-007-022-MY2, and MOST 104-2221-E-007-093-MY3), Taiwan. (Anup Kumar Sahoo and Chan-Shan Yang contributed equally to this work.) (Corresponding author: Ci-Ling Pan.) A. K. Sahoo is with the Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (e-mail: anup140387@gmail.com). Publisher Copyright: © 2011-2012 IEEE.

PY - 2019/7

Y1 - 2019/7

N2 - 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.

AB - 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.

KW - Birefringence

KW - liquid-crystal (LC) devices

KW - nanomaterials

KW - phase shift

KW - spectroscopy

KW - terahertz (THz)

KW - transparent conductive coatings

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SP - 399

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JO - IEEE Transactions on Terahertz Science and Technology

JF - IEEE Transactions on Terahertz Science and Technology

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ER -

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

Abstract

Keywords

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