Tuesday, 26 March 2013

Resonance enhancement of terahertz metamaterials by liquid crystals/indium tin oxide interfaces

Optics Express, March 2013, Vol. 21, Issue 5, pp. 6519-6525 (2013)
doi: 10.1364/OE.21.006519.

Authors: Zhen Liu, Chia-Yi Huang, Hongwei Liu, Xinhai Zhang, and Chengkuo Lee


This work fabricates a terahertz (THz) metamaterial device, whose structure consists of split ring resonator array/ plastic substrate/ Indium Tin Oxide (ITO) film/ liquid crystals/ ITO film/ plastic substrate. Experiment results show that the resonance of the THz metamaterial device can be enhanced as voltage is applied to the liquid crystals. The enhancement will be more significant as higher voltage applied. The resonance enhancement is attributed to the fact that the liquid crystals/ITO interfaces exhibit the large difference in terms of refractive index between the two materials in THz regime. The interfaces reflect the incident electromagnetic wave and cause the reflected wave to enhance the resonance of the metamaterials. As those frequency-tunable metamaterial devices show different resonant transmittance at different frequencies, which is undesired, the liquid crystals/ITO interfaces can improve those frequency-tunable metamaterial devices with a constant transmittance at different frequencies.

... Figure 2 shows the transmission spectrums of the metamaterial device at applied voltages of 0
V, 4 V and 10 V. These spectrums are obtained by THz time-domain spectroscopy
(TeraView, TPS Spectra 3000) in transmission mode, where the non-polarized THz electromagnetic
wave as the probe light is normally incident to the metamaterial device from the side of the
SRR array...

More details at: http://www.opticsinfobase.org/oe/fulltext.cfm?uri=oe-21-5-6519&id=250680

 +The Optical Society (OSA)
OCIS codes: (160.3710) Liquid crystals; (160.3918) Metamaterials; (300.6495) Spectroscopy,
terahertz; (230.7408) Wavelength filtering devices.


This work was supported in part by SERC of the Agency for Science, Technology and Research (A*STAR) at the +National University of Singapore