Abstract-Study of asymmetric U-shaped resonator at terahertz frequencies

• Zhou Yang
• Qingli Zhou
• Wen Long
• Chenyu Li
• Yulei Shi
• Ani Wu
• Jianfeng Liu
• Cunlin Zhang

http://www.sciencedirect.com/science/article/pii/S0030401816300906

We demonstrate the asymmetric U-shaped array exhibits different spectral patterns in response to incident terahertz wave with horizontal and vertical polarizations. In the horizontal incident polarization, where terahertz electric-field E_in is in parallel with the bottom bar of U-shaped structure, the two-absorption-dip transmission spectrum is similar to that of a typical split-ring resonator. When E_in is perpendicular to bottom bar, an interesting phenomenon comes up with three dips. This differs from the split-ring resonator which only has one dip in the transmission spectrum. The bottom-bar length also has significant impacts on frequency-shift and absorptive depth related to this resonant phenomenon.

Abstract-Transmitted spectral modulation of double-ring resonator using liquid crystals in terahertz range

Huijuan Sun

Beijing Institute of Technology (China)

Qingli Zhou, Chenyu Li, Ani Wu, Cunlin Zhang

Capital Normal Univ. (China)

Xiumin Wang

Beijing Univ. of Civil Engineering and Architecture (China)

http://proceedings.spiedigitallibrary.org/proceeding.aspx?articleid=1811722

Proc. SPIE 9042, 2013 International Conference on Optical Instruments and Technology: Optical Systems and Modern Optoelectronic Instruments, 90421E (December 31, 2013); doi:10.1117/12.2038128

Metamaterials with subwavelength structural features show unique electromagnetic responses that are unattainable with natural materials. Recent research on these artificial materials has been pushed forward to the terahertz region because of potential applications in biological fingerprinting, security imaging, remote sensing, and high frequency magnetic and electric resonant devices. Active control of their properties could further facilitate and open up new applications in terms of modulation and switching. Liquid crystals, which have been the subject of research for more than a century, have the unique properties for the development of many other optical components such as light valves, tunable filters and tunable lenses. In this paper, we investigated the transmitted spectral modulation in terahertz range by using liquid crystals (5CB and TEB300) covering on the fabricated double-ring resonators to realize the shift of the resonance frequency. Our obtained results indicate the low frequency resonance shows the obvious blue-shift, while the location of high frequency resonance is nearly unchanged. We believe this phenomenon is related to not only the refractive index of the covering liquid crystals but also the resonant mechanism of both resonances. © (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.