Twisted nematic liquid crystal cells with rubbed poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) films for active polarization control of terahertz waves
| Autor: | Hiroshi Ono, Moritsugu Sakamoto, Tomoyuki Sasaki, Hiroyuki Okamoto, Kohei Noda, Hiroki Okuyama, Nobuhiro Kawatsuki |
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| Rok vydání: | 2017 |
| Předmět: |
Materials science
business.industry Terahertz radiation General Physics and Astronomy 02 engineering and technology 021001 nanoscience & nanotechnology Polarization (waves) 01 natural sciences Spectral line 010309 optics chemistry.chemical_compound Optics chemistry PEDOT:PSS Liquid crystal 0103 physical sciences Electrode Optoelectronics 0210 nano-technology business Quartz Poly(3 4-ethylenedioxythiophene) |
| Zdroj: | Journal of Applied Physics. 121:143106 |
| ISSN: | 1089-7550 0021-8979 |
| DOI: | 10.1063/1.4981244 |
| Popis: | We fabricated a terahertz (THz) polarization converter using a twisted nematic (TN) liquid crystal (LC) cell. Poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) films coated on quartz glass substrates were used as electrode layers in the TN LC cell. The PEDOT/PSS films were rubbed unidirectionally using a rayon cloth to align the nematic LC, thereby also serving as an alignment layer. The azimuthal surface anchoring strength of the PEDOT/PSS films was measured to be 5 × 10−4 J/m2 using the Neel wall method, which is similar to that of typical polymeric alignment layers. The optical constants of the PEDOT/PSS film in the THz range were also characterized using the Drude-Smith model, and the results indicated that the PEDOT/PSS films could be used both as transparent electrodes in the THz range and as alignment layers for the LC. The electro-optical properties of the fabricated TN LC cell were also investigated using a polarized visible laser and THz time-domain spectroscopic system. In particular, the transmission spectra and polarization conversion property of the TN LC cell in the THz range were theoretically analyzed based on a stratified model that considers optical anisotropy, absorption, and multiple interference. This work substantiates the advantages of TN LC cells with rubbed PEDOT/PSS films useful for THz polarization converters with electrical tunability. |
| Databáze: | OpenAIRE |
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