Abstract-Polarization-dependent electromagnetic responses in an A-shape metasurface

Ning Zhang, Quan Xu, Shaoxian Li, Chunmei Ouyang, Xueqian Zhang, Yanfeng Li, Jianqiang Gu, Zhen Tian, Jiaguang Han, and Weili Zhang

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-25-17-20689&origin=search

We numerically and experimentally demonstrate polarization-dependent terahertz responses in a proposed metasurface of A-shape resonators. With the horizontal polarization incidence, the observed transmission window is formed by two resonance dips, corresponding to the inductive-capacitive resonance at the lower frequency and the high-order antisymmetric resonance at a higher frequency, respectively. When the incident wave is perpendicularly polarized, the transmission window arises from the plasmon-induced transparency spectral response. The origin of the polarization-sensitive resonance properties is revealed by mapping the electric field and terahertz-induced surface current in the proposed metamaterials. Moreover, the influence of the geometry of the A-shape microstructures on the transmission spectra is analyzed. These polarization-dependent metamaterials may provide more degrees of freedom in tuning the electromagnetic responses, thus offering a path toward robust metamaterials design.

© 2017 Optical Society of America

Abstract-Terahertz surface plasmon polariton waveguiding with periodic metallic cylinders

Ying Zhang, Shaoxian Li, Quan Xu, Chunxiu Tian, Jianqiang Gu, Yanfeng Li, Zhen Tian, Chunmei Ouyang, Jiaguang Han, and Weili Zhang

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-25-13-14397

We demonstrated a structure with periodic cylinders arranged bilaterally and a thin dielectric layer covered inside that supports bound modes of surface plasmon polaritons at terahertz frequencies. This structure can confine the surface plasmon polaritons in the lateral direction, and at the same time reduce the field expansion into space. We examined and explored the characteristics of several different structures using scanning near-field terahertz microscopy. The proposed designs pave a novel way to terahertz waveguiding and may have important applications in the development of flexible, wideband and compact photonic circuits operating at terahertz frequencies.

© 2017 Optical Society of America

Abstract-Molecular Recognition and Interaction between Uracil and Urea in Solid-State Studied by Terahertz Time-Domain Spectroscopy

Jingqi Yang , Shaoxian Li , Hongwei Zhao , Bo Song , Guoxin Zhang , Jianbing Zhang , Yiming Zhu , and Jiaguang Han

J. Phys. Chem. A, Just Accepted Manuscript

DOI: 10.1021/jp506045q

Publication Date (Web): October 28, 2014

Copyright © 2014 American Chemical Society

http://pubs.acs.org/doi/abs/10.1021/jp506045q?journalCode=jpcafh

Using terahertz time-domain spectroscopy characterization, we observe that urea is able to recognize and interact with uracil efficiently even in solid phase without involving water or solvents. A cocrystal configuration linked by a pair of hydrogen bonds between uracil and urea was formed. Terahertz absorption spectrum of the cocrystal shows a distinct new absorption at 0.8 THz (26.7 cm-1) which originates from the intermolecular hydrogen bonding. Both mechanical milling and heating can accelerate the reaction efficiently. Density functional theory was adopted to simulate the vibrational modes of the cocrystal and the results agree well with the experimental observation. Multi-techniques, including powder X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy were performed to investigate the reaction process and presented supportive evidences. This work enables in-depth understanding of recognition and interaction of urea with nucleobases, and comprehending the denaturation related to RNA. We also demonstrate that terahertz spectroscopy is an effective and alternative tool for online measurement and quality control in pharmaceutical and chemical industry.