Abstract-Off-resonance and in-resonance metamaterial design for a high-transmission terahertz-wave quarter-wave plate

Zhengli Han, Seigo Ohno, Yu Tokizane, Kouji Nawata, Takashi Notake, Yuma Takida, and Hiroaki Minamide

https://www.osapublishing.org/ol/abstract.cfm?uri=ol-43-12-2977

This Letter describes a novel metamaterial design by employing off-resonance and in-resonance excitation for a high-transmission terahertz-wave quarter-wave plate (QWP). The device is demonstrated with a thin film metamaterial with double-layer split ring resonators (SRRs). Different from a usual resonant metamaterial device, here we design the work frequency off from the inductor-capacitor (LC) resonance for the TE mode, while in a dipole resonance for the TM mode to obtain the artificial birefringence. Rectangular SRRs in this Letter provide a choice to optimize the off-resonance and in-resonance excitation, to assist the double-layer design for high transmission. Converting a linearly polarized wave to circular polarization with our QWP, the experiment confirms a transmittance of 0.8 and an ellipticity of 0.99 at 0.98 THz. The developed thin film device is flexible and has a thickness of 48 μm (sub-wavelength). This is an advantage for potential integration in systems where overall device compactness is required.

© 2018 Optical Society of America

Abstract-Teeter-totter effect of terahertz dual modes in C-shaped complementary split-ring resonators

Zhiqiang Song¹, Zhenyu Zhao^1,a), Hongwei Zhao², Wei Peng³, Xiaoyong He¹ and Wangzhou Shi¹
http://scitation.aip.org/content/aip/journal/jap/118/4/10.1063/1.4927845
1 Department of Physics, Shanghai Normal University, Shanghai 200234, China
2 Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
3 State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
a) Electronic mail: zyzhao@shnu.edu.cn
J. Appl. Phys. 118, 043108 (2015); http://dx.doi.org/10.1063/1.4927845

A teeter-totter effect of terahertz (THz) resonant modes in C-shaped complementary split-ringresonators (CSRRs) is observed. The dual resonant mode transmission enhancement was investigated using THz time-domain spectroscopy. The intensity of the lower-frequency resonance modes increases monotonically with the CSSR gap width, which is accompanied by a monotonic decrease in the intensity of the higher-frequency resonance modes. The origin of the dual resonant modes is numerically explained by the electromagnetic energy density distribution and surface current analysis. The inductive-capacitive resonance dominates the lower frequency mode, while the dipole oscillation dominates the higher frequency mode. By tuning the gap of the CSRR, an equilibrant transmittance of above dual resonance modes can be designed. This teeter-totter effect promises a possible application of CSSRs as potential dual-bandpass filters in the THz-region.