Abstract-Voltage-controlled liquid-crystal terahertz phase shifter with indium–tin–oxide nanowhiskers as transparent electrodes

Chan-Shan Yang, Tsung-Ta Tang, Po-Han Chen, Ru-Pin Pan, Peichen Yu, and Ci-Ling Pan  »View Author Affiliations

Optics Letters, Vol. 39, Issue 8, pp. 2511-2513 (2014)
http://dx.doi.org/10.1364/OL.39.002511

http://www.opticsinfobase.org/ol/abstract.cfm?URI=ol-39-8-2511

Indium–tin–oxide nanowhiskers were employed as transparent electrodes in a liquid-crystal terahertz phase shifter. Transmittance of the device was as high as ∼75%. Phase shift exceeding π/2 at 1.0 THz is achieved in a ∼500  μm-thick cell. The driving voltage required for the device operating as a quarter-wave plate was as low as 17.68 V (rms), an improvement of nearly an order of magnitude over previous work.

© 2014 Optical Society of America

Abstract-Liquid crystal terahertz phase shifters with functional indium-tin-oxide nanostructures for biasing and alignment

Chan-Shan Yang^1,2, Tsung-Ta Tang³, Ru-Pin Pan⁴, Peichen Yu⁵ and Ci-Ling Pan^1,6,a)

1 Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
2 Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
3 Taiwan Semiconductor Manufacturing Company, Hsinchu, Taiwan
4 Department of Electrophysics, National Chiao Tung University, Hsinchu 30078, Taiwan
5 Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan
6 Frontier Research Center on Fundamental and Applied Science of Matters, Hsinchu 30013, Taiwan
a) Author to whom correspondence should be addressed. Electronic mail: clpan@phys.nthu.edu.tw
Appl. Phys. Lett. 104, 141106 (2014); http://dx.doi.org/10.1063/1.4871255

Indium Tin Oxide (ITO) nanowhiskers (NWhs) obliquely evaporated by electron-beam glancing-angle deposition can serve simultaneously as transparent electrodes and alignment layer forliquid crystal (LC) devices in the terahertz (THz) frequency range. To demonstrate, we constructed a THz LC phase shifter with ITO NWhs. Phase shift exceeding π/2 at 1.0 THz was achieved in a ∼517 μm-thick cell. The phase shifter exhibits high transmittance (∼78%). The driving voltage required for quarter-wave operation is as low as 5.66 V (rms), compatible with complementary metal-oxide-semiconductor (CMOS) and thin-film transistor (TFT) technologies.